Laurie

If you're getting 2,700 fps with the 175 SMK and good groups, that really is an excellent factory load. Handloading will allow improvements, but not the large step change often associated with an upgrade from off the shelf ammo. Everything I hear about GGG suggests they produce good stuff - a far remove from RG 155gn 'Bisley Match'!

Assuming that the 175gn GGG uses the Sierra MK of that weight (as the NRA match 155 does), I'm not too surprised. At modest MVs, the old 175 often gives amazingly good good groups and is very barrel / chamber / velocity tolerant, at least until you try to drive it fast. I shot one of my smallest ever 100 yard 5-shot groups with an IMR-4064 handload with this bullet in 308 Win, moreover in a factory rifle, an early FN SPR tactical / sniper 24-inch barrel job. It was a genuine 0.1-inch and the rifle/handload shot very well at 300 yards too in the benched winter series 'Precision Rifle' matches we used to shoot at Diggle.

For short / mid-range use, if you can get factory ammunition with this bullet to perform as well as that, it becomes difficult to justify handloading at times. Unfortunately, the old 175 with its modest 0.243 average G7 BC and the likely modest MVs from the GGG version isn't competitive these days in F/TR at 500/600 (unless shooting in a flat calm) even in club level competition and is ballistically hopeless beyond 800 yards. I quickly found this with my 175 SMK / 4064 handloads, the Catch 22 being that the tight groups came with ballistically sub-optimal low MVs in the 2,600s and the higher MV loads that met the external ballistics requirement wouldn't produce groups under 0.75-MOA.

With a good 155 such as the 155.5gn Berger LRBT Fullbore the better long-range bullets up to and including the 185gn Juggernaut, a good F/TR rifle will average under 0.3-MOA at 100. Note the word average as <0.3-MOA means the best individual groups will be under 0.2-inches. My Osprey Rifles (now GS Precision) built Stolle Atlas will still shoot 0.15-Inch groups with the 155.5gn Berger at an MV that has dropped to through throat wear to 3,027 fps (32-inch barrel) despite it having seen nearly 3,000 rounds down the barrel. The average though will be about 0.3.

These bullets at suitable velocities will hold under half-MOA elevation at 1,000 yards, most of a 20-round string in quarter-MOA or thereabouts, unless on a range where wind effects also have an elevation component as in Diggle and Blair Atholl when the wind comes from some directions. The heavier 30-cal bullets in the 200/210gn bracket don't usually group quite as tightly or hold as good elevations at long ranges but buck the wind better and so tend to give better L-R scores over a season. Even so, I've seen those 101RC guys who shoot national level F/TR and who generally like and still stick with the old 210gn Berger BT put five shots into ragged holes in loads testing at 100 at Diggle off the bench despite using not at all optimal bipod front-support.

18 hours ago, ronzi83 said:

But now i was thinking to actually try 147eld with RS60. Some people say it is really temp stable and great powder, but i have never worked with it.

RS60 is Alliant Reloder 17 under another name. American experience says this is one of the most temperature affected powders on the market and many competitive US shooters have dropped it for this reason.

It will potentially give very velocities in this cartridge, but if loaded to maximum pressure / MV it will accelarate barrel wear significantly compared to RS62 or other non high-energy grades.

At 40/41gn that sounds like N150  ??????

The 139 Scenar remains an excellent and dependable performer in the calibre as does the antediluvian 142gn Sierra MK and both cost a lot less than the newer designs. The new heavier Hornady ELDs have impressive form factors / BCs and this is backed by Bryan Litz's tests so isn't a case of OTT claims from the manufacturer as would almost certainly have been the case some years back. Price and availability though? Ouch!

We are also seeing a new generation of 'Super-VLDs' - impressive BCs, but at the expense of very long projectiles that are inherently less stable than older designs and which have 'aggressive' secant ogives ......... and when I say 'aggressive' I mean really aggressive, a much sharper transition than that of the original Berger VLDs of a generation ago. Some of these designs have to be the very devil to 'tune', albeit as always individual barrels and rifles will vary enormously in their tolerance or otherwise.

Another issue with these super long, super-VLD forms is that they don't suit the 260 well in magazine use as they end up seated so deeply in the case at the required 2.800-2.880" COALs demanded by magazine dimensions. No issue in suitably throated rifles in single-shot mode, but many people are buying or fancy PRS type rifles or that evergreen object of British shooter lust, whatever is the latest AI model. The shorter case 6.5 Creedmoor must be seeing 'issues' here too with the newest designs and probably only the yet shorter 6.5X47mm Lapua remains unaffected (but only if it has the 'freebore' to suit the longer bullet designs).

A couple of thoughts on alternatives. First for seriously COAL constrained set-ups especially with the 260, have a look at the 130gn Berger Tactical OTM AR-Hybrid. This is a superb design that combines good BC with a shorter nose to suit 2.8-inch COALs and the 'Hybrid' form ogive that allows it to be jumped considerable distances and yet stil perform well. They are unfortunately not plentiful on the market, and certainly not cheap - quite the reverse in fact! (Also many people say - I can't finds these bullets listed anywhere. The reason for this is that Berger has them in its small 'Tactical OTM' section not 'Target' and many people never look at this listing.)

Second, there is another older but superb design available which is well known to US 6.5mm aficionados, but I rarely if ever hear mentioned this side of the pond - the 140gn Berger Target BT Long Range. This is the 6.5 equivalent to the 185gn 308 'Juggernaut' - a long-nose tangent ogive and easy to tune bullet with a good but not exceptional BC. It also has a short bearing surface allowing it to be driven faster than many competitor designs within safe pressures. This is my favourite 6.5 long-range bullet for the 260 and 6.5X55mm. Again, they're not common largely because few handloaders here know of them never mind order them ........... and they don't conform to the common Hybriditis disease condition that is like an epidemic causing great wallet sickness. Being a Berger though (of any vintage or type) it's good but never cheap.

Lastly, do you have to have the highest possible BC design? .... or even one in the top half of the rankings? A lot of CSR type shooters like the 140gn Nosler Custom Competition and there are sources around for bulk buys from Europe at bargain prices if what is said on UKV is correct. Ah, but it's a blunt, 'low BC' bullet, surely? Yes, it is by 6.5 standards, but is way ahead of equivalent 308s and will remain supersonic at modest MVs to 1,000 yards. Sure, if you're competing seriously in long-range F-Class or similar, you want the best you can get and afford ........ but for occasional long-range or days on a Bisley electronic target on Stickledown. And at 300-800 yards most shooters won't notice a difference from the ELDs etc, especially as they are very easy to 'tune' and seem to suit most barrels. I used these old-fashioned bullets in a 1,000 yard BR comp a couple of summers back in an out of the box Savage 12 LRP with 26-inch barrel at a mere 2,710 fps MV (Creedmoor - this load with RS62 shot quarter to third inch at 100) and got a half-MOA group as best of four. (At a G7 BC of 0.281 from Litz, 2,710 fps MV saw an estimated 1,000 yard retained speed of 1,379 fps still comfortably above the transonic speed range on Diggle at nearly 1,000 ft ASL on a warm day.)

Don't forget the T3X Varmint if you can live with a synthetic stock, available in 260 and 6.5X55mm with a 600mm barrel length option.

Alan Seagrave has used the older T3 Varmint / 600mm / 6.5X55mm to frequently win the 1,000 yard Factory Rifle Class in benchrest matches at Diggle for some time now and has shown it is competitive against rifles like the Savage 12 'Precision' in its 6.5-284 F-Class and 6mm BR Benchrest versions at this distance.

(The Savage 12s are another option for 1,000 yard out of the box performance, the two mentioned above, 12 FTR in 308, and LRP (Long Range Precision) in 260 or 6.5 Creedmoor. Sadly they're nothing like as cheap as they were some years ago when we first saw them here.

The F-Class, BR, and FTR are single-shot jobs with 30-inch barrels; the LRP a DB magazine with 26-inch barrel.)

You should be able to get higher MVs than 2,850 from the SAUM especially with RS70 which is one of Nitrochemie's 'high-energy' grades and has the advanced 'EI' infused deterrents technology.

Nodes generally occur at around 100-150 fps MV intervals, sometimes smaller intervals though, so you need to work up in small steps and see when you hit the next one at higher velocities, checking that pressures remain acceptable for your barrel and in your highest local temperature conditions.

See:

http://bulletin.accurateshooter.com/2018/05/good-news-for-gunsmiths-major-itar-changes-coming/#comments

The detail isn't available yet, but it looks like many of the things we buy from the USA may be exempted. If so, good news.

Insofar as SR primers go, there is NO relationship between so-called 'magnum' primers and 'magnum' (hotter) performance. Magnum SR (and BR types) primers have thicker cups but often have the same pellet as the standard grade inside. Some individual models (including non-magnums) are slightly warmer than others.

See first conclusion (commentary on Table 1) in:

http://www.targetshooter.co.uk/?p=2662

What I increasingly see is the difference SR primers can make to performance - not in MVs but in matching the rest of the load and changing group sizes. This has two results. First some experimentation with primers may be necessary during load development to get best results, and 2) once you've settled on a primer model stick with it. Changing primer (sometimes even buying a new lot of an existing one) often requires the load to be fine-tuned again.

They have already been used in national level comps ........... BUT the tablets used as monitors are supplied to competitors by the organisers. They obviously have no ballistics etc apps installed and presumably cannot be communicated with by third parties. As well as meeting these requirements, there is the advantage to the line officers that everybody has the same kit, so any log-on or reception issues can be more easily resolved, unlike when every competitor is using his or her own kit.

ICFRA will no doubt update its rules on this issue in due course.

8 hours ago, johngarnett said:

That system is a graphical method of a standard TR plotting sheet. On your plot sheet you put down estimated wind and then plot your shot. You then have to 'calculate' the true wind. This way shows you what you needed for wind for the last shot. There is/was a Canadian company making the Plot O Matic. It was very good but a bit pricey!

I have seen the Canadians using this very usefully.

Get practising!!

JohnG

The last I heard Milcun (Linda Miller and Keith Cunningham, the Canadian range owners and marksmanship training outfit) owned the rights to the onetime Plot-O-Matic and sold it under another name, as well as using it in some of their training work. It was originally developed by a Canadian TR shooter. It's not shown on their website anymore as far as I can see.

http://www.milcun.com/index.html

It doesn't do anything that a good standard paper plot won't except maybe show things a little more clearly, and it exacerbates the main problem that plotting poses for most tyros in this activity - time and distraction. Some people never get to grips with producing a full plot as it adds too much workload with all the other things you've got to do in the 45 seconds allowed between target reappearance and taking the shot.

On the use of personal phones and tablets with electronic targets, I don't see that lasting past the initial learning curve / familiarization stage. The Americans went to match organiser-issued tablets from day one with their F-Class Nationals at Lodi last year and on other ranges where they've since being used. They have really strict rules on no competitor owned electronic or communications device other than  timers and earmuffs being allowed by competitors ahead of a line 30 metres or somesuch behind the firing line - having your phone ring whilst on your person whilst taking part in an major match (or club one for all I know too) is a DQ or points penalty job. This is presumably to eliminate possible distractions to other competitors, but primarily as I understand it to prevent the use of computed wind reading / shot analysing etc aids, illicit communications from a friend behind the firing line coaching etc -  as BoltHead says that's what's in the ICFRA rule book.

I should have qualified my reply to say N560 which is very much slower burning than N160, and in fact often acts as a slower burning powder than N165. My experience is that it can be finicky and also need max pressure loads to perform consistently. In sporter length barrels, one symptom of it being unhappy is muzzle flash like I've never seen with anything else! Viht doesn't list this powder with any bullet weight in the cartridge.

N550 should be happier, but if you look at the recently revised Viht data, both N550 and N160 are shown for the 160gn Nosler Accubond, the nearest to what you're using. N160 perhaps a little surprisingly gives another 50 fps over N550.

Hornady in its most recent manual has data--sets for both 280 Rem and 7X64, but no Viht powder loads - in fact there is not much Viht data in this manual anymore and recent additions like the 6.5 Creedmoor have none at all (likewise Sierra). Both it and Lyman 50th just out (for the 280 alone here) show best results from IMR-4350 and for best MVs IMR/H4831.

So, this gives an indication of post-Reach alternatives:

IMR-4451 (for 4350) and when it arrives IMR-4955 (for the 4831s)

Viht N160 which despite being shown as equivalent to IMR-4831 in most burning rate charts often acts more like the 4350s and at the least is somewhere between the 4350s and 4831s. See Viht's data.

Viht N550

Ramshot Hunter (Hornady lists 52.6gn max for its 162s for 2,600 fps in a 22-inch barrel Sauer 101, not the highest MV in the table) QuickLOAD computes another 90 fps from this combination for nearly 2,700 fps and a very good match to the cartridge and bullet. (Using the 162 AMax as I don't have the ELDs in my version.)

Alliant Re19 and 22 should both work. QuickLOAD suggests Re19 is an excellent match ballistically, but if you're chasing MV several more grains Re22 and a compressed load gives almost as high MVs as you can safely get.

Reload Swiss lists loads for the 7X64 but the nearest bullet to the Hornady 162 is the 168gn Sierra MK and shows loads for RS60 / RS62 / RS70 / RS80. (80 is hopeless - far too slow burning.) QuickLOAD suggests RS62 and RS70 are excellent matches.

21 minutes ago, Scotch_egg said:

As for powder I will be going to a Vihtavuori N550-N560 due to the shorter barrels Blaser use and the fact I’m  not putting several rounds down at a time causing heat. 

You may encounter considerable muzzle blast and flash with anything under a really high pressure load.

37 minutes ago, Hobbit said:

Laurie

Thank you - I was hoping you would jump in 

That is a great tip on the mandrels - does this mean the 7mm mandrel for example leaves the brass just sub 7mm in diameter so there is some neck tension??

Thanks

Yes

The 7X64 is very close dimensionally and ballistically to the 280 Remington although neither brass nor loaded cartridge is interchangeable. (Actually, it's the other way round as 7X64 is very much senior to the US upstart near-copy!) The advice on loads is to use 280 Rem data and subtract 5% from the maximum for safety. So look up pet loads on the 280 if you don't find much on the Brenecke.

Redding Deluxe are standard non-bushing dies. Good quality IME. If the neck tension is too high, remove the expander in the sizer die and get or if you already have one use, a mandrel type expander die which allows interchangeable mandrels designed for expanding the neck before neck-turning. I use the Sinclair expander die body and the same company's 28E model expander on all my match sevens and the degree of neck tension is just where I want it. The K&M equivalent should be fine too. Lube the inside of the neck before use, or else shell out for a very expensive carbide mandrel.

https://www.vihtavuori.com/reloading-data/rifle-reloading/?cartridge=82

I'd have thought N160 is well suited to the cartridge, N165 for 170gn and heavier.

Remember the small primer / flash-hole effect on pressures and MVs compared to large primer results. In 308 Win, the norm is that 'Palma' brass needs somewhere between 0.5 and 0.7gn more powder to produce the same MV as the same internal capacity standard LR primer case with H4895 and H. VarGet class powders.

However, when I did side by side  tests of  SR primers in 308 Win (written up in Target Shooter online) with the 167gn Scenar and Viht N150, I started out with side by side load development using Lapua 'Palma' and standard cases in the same range session. I found with this powder which has a not dissimilar burning rate to RS62, that a 1.4gn heavier charge was needed in the SR Brass to get equivalent MVs. (the 260 is of course an LR primed case, so gets the hotter ignition.)

Vince ('The Gun Pimp') has just put up the final part of my Small Rifle primer test in 308 Palma brass on Target Shooter online.

Just to back up Laurie's findings: I have used RS52 with 155 hybrids extensively in FTR comps. Having meticulously programmed all case/cartridge data I find that to make QL results tally with my findings I need to increase the burning rate of RS52 to 0.5500. Which is @10%. This is with the Lap palma case and small murom primer. MV measured with Labradar. Now trying heavier projectiles and being v cautious! When using Varget with the above combo I needed to reduce the burning rate by @5% when using the small primer.

Edit: So in my case with my rifle the difference was @15% if you use QL std powder data! Please be careful everybody!

Interesting!

As an aside, what do you do re 'jump' for the 155gn Hybrid? I've not found this an easy bullet to 'tune' - in my chamber / barrel it seems to need a large jump (40 thou' or more) before it'll perform. (By contrast, the 168gn Hybrid only performs if treated like a VLD and seated 'in' - not just me who has found that so it seems to be a general feature for this model. I'm not over-impressed by 30 calibre Hybrids as the Berger / Litz claims of tangent ogive like flexibility simply haven't stood up to scrutiny for me so far.)

Whatever you do, don't trust QuickLOAD with RS52. IME it seriously underestimates pressures and MVs.

As an example, to take one of my two main FTR loads - RS52 + 168gn Berger Hybrid in Lapua Palma SR brass - setting everything up correctly in QL (actual case overflow water capacity; COAL; bullet in the lands and severely enhanced shot start pressure), QuickLOAD predicts 55,198 psi PMax and 2,870 fps MV from a 32-inch barrel for my load. As the small primer brass normally needs at least a half-grain additional powder to achieve the same MVs as the standard LRP Lapua 308 case, reducing the charge weight in QL by that amount to obtain the equivalent charge for a Lapua LRP case load sees the the prediction reduce to 53,457 psi / 2,842 fps.

The actual MV is 2,960 fps which will need somewhere around the full SAAMI 62,000 psi maximum chamber pressure to achieve and the QL calculation is 1.7gn RS52 awry on the 'wrong side', equivalent to maybe 2.2gn 'out' taking the small primer factor into account. I have seen similar wrong results in other cartridges.

It's a great powder. A simple rule of thumb I have that has worked for me in three cartridges so far including 308 is to take Hodgdon's starting load for VarGet, use that and work up towards Hodgdon's maximum. You can usually go a little higher than the VarGet max and will get 25-40 fps higher velocities, but you may not want to go there anyway getting good results and high enough MVs at somewhat lower charges.

When it was first made available as a bulk powder under the Nitrochemie OEM of EI-N130 without any loading data, its working name was 'Elcho-15' as it was believed to behave similarly to VarGet and Alliant Re15. I did side by side tests in 308 against these two powders with a variety of bullet weights and found that what is now packaged as RS52 performed very well at the same charge weights as the other two, but could be loaded higher and usually outperforms them.

Taking my rule of thumb, Hodgdon lists a load for the 155gn Sierra MK, 2.775" COAL, Winchester case, F210M primer and H. VarGet as starting load 44.0gn, maximum 47.0gn (compressed) for 49,400 Copper Units Pressure showing this an old load (pre Piezo crystal psi pressure gauge measurement). The SAAMI MAP is 52,000 CUP under this measurement method, so the maximum is comfortably within that powder's top pressure levels. However, Winchester brass has a greater internal capacity than Lapua, so another of my rules of thumb has me reduce any such recommended load by 1gn on changing the case.

So, to use Varget as a guide to RS52, work on starting load 43gn with a maximum somewhere around 46gn, but in practice you'll likely find that you can go higher without pressure issues.

Both the original (all alloy) Tier-One and the 2/3 metre-footprint carbon model are very good indeed. Likewise the Dolphin AB (another carbon fibre legs model) and the alloy Shooting Shed Stotteben. (The Stotteben is the widest of the wide at even more than 660mm footprint when at its lowest setting.)

They and the SEB Joy-Pod are all effective, easy to set up and use and can be seen being used by our top international FTR shooters. Bearing in mind David Bonwick (Shooting Shed) only making occasional limited production runs of his Stotteben, you see it in use by a disproportionate number of such competitors, but the SEB is likely the most popular at top club, and national levels.

I have both the Dolphin AB and Stotteben models currently on loan for review, have shot them with F-Open rifles up to 284 Win with 180s and regard them as very good indeed. I'll shortly do a write-up for them as a follow-up to that for the Tier-One Carbon in Target Shooter. The best one? It's a personal preference issue - I'd be happy to use any of the trio (and/or the SEB JoyPod). The Tier-One models with their spoked mariner wheel adjusters are probably the easiest to make minor in-comp height adjustments excepting of course the SEB with its joystick. (But it's remarkable how many people lock that one up solid and shoot without using the joystick facility.)

strange the website quotes 28 inch .

When first introduced the 6.5 Creedmoor version was listed as 24-inches on Sabatti's website and that's what the original deliveries were. An acquaintance who is in the gun trade fancied one, but as it was entirely for range use queried whether 26-inches was available and told 'yes - as a special order, will take an estimated six weeks' - 3 months later he was still waiting.

Then .... every one arriving was 26-inches in this calibre. 28-inches I've not seen quoted anywhere and it would make no sense for a rifle in this category / market.

I suspect the ELD-Ms are struggling to obtain a foothold against existing Berger products for the serious long-range competitor, in many calibres anyway. Looking at US forums, the new 6.5s seem to be gaining traction especially amongst 6.5 Creedmoor shooters. The 143gn 'X' hunting version is particularly highly regarded for both precision and its expansion characteristics. Now that we can again buy and load expanding bullets for any purpose, this could well be a very good choice for the multi-role shooter who wants to use a deerstalking load on paper.

Other calibres? Judging by some heavy discounting by the major US suppliers, I doubt if they're doing very well. I know one top GB FTR competitor tried the .308 208gn ELD-M and quickly went back to the 200gn Berger Hybrid. They shot very well at shorter distances, but simply didn't match the Berger's 1,000 yards performance and consistency. Berger has really got 308 sewn up - there is at least one outstanding model in every weight category - the 155.5gn BT, 185gn BT, and 200gn Hybrid. A significant number of top northern FTR shooters still use the older 210gn Berger BT when shooting 'heavies'.

For many short to mid-range shooters, or those who don't need 1,000 yard 'ultra' performance, they may be very good choices - but only if they offer a substantial discount to Berger prices. So far at any rate, many models don't appear to justify premium pricing. In that case, they may have to be judged against Sierra's TMKs rather than Bergers.

As an aside, I am surprised that no-one yet has mentioned the newer TMK175s for 1000 yd F-Class/TR as their BC is significantly up on the older smk and they're still reasonably priced.

I've been asked several times now if I've tried them ... the answer so far is 'no'. There has been a flood of new bullets recently, and I shoot 308 a lot less these days than I once did.

My limited experience with the TMKs - 160gn 7mm only - has been very good. I have some other versions in other calibres which I'll try in due course, but haven't acquired any 30s yet. As I'm about to use my last 105 Berger 155.5s up in a test series for Targetshooter online, I might buy a couple of hundred 168 and 175gn versions to see how they go.

I've had excellent results with this bullet in Lapua Palma brass over RS52 at getting on for 3,000 fps. Unlike the 155.5 and 185 BT Long-Range designs, it's fussy about seating depth / jump. To get it to shoot, I had to treat it like a VLD and put into the lands. Others have said the same thing to me. (So far, in 308 at any rate, every Hybrid has behaved differently for me. IME they are NOT the length-tolerant design Berger claims - can't comment on other calibres.)

There is still the residual 'taint' of the 168gn weight too for the calibre. When I started with the 168 Hybrid, a surprising number of people said - no good at long range, all 168s are useless for that!

Being jump-fussy, that alone understandably puts a lot of Effers off. If it's 'fussy', it might also be unpredictable / inconsistent. The 155.5 and 185 BTs are so tolerant, a slight change in die setting, bit of leade erosion etc doesn't affect performance, so just load the things up and go shoot ... and shoot ... and shoot. One less thing to worry about.

That's the theory anyway. Whether it works in practice, we'd have to see. The bullet has to be a good fit/match to the barrel in any event. Some bullets just don't shoot in some barrels.

How I expect it'll work out is that you find something that is 'almost there' and also has a small ES/SD, and the tuner (hopefully!) does what it says on the tin and 'tunes' the load that last bit through a little adjustment to its setting.

The Labradar is sometimes falsely triggered by an adjacent shooter using something noisy, muzzle brake equipped jobs especially. The start emitting and recording trigger is sound - there are two small internal microphones about half way up the body, one on each side to allow placement either side of the firearm.

Even shooting off benches placed pretty close together, if a neighbour's shot triggers the radar, the other person's bullet track bullet is off the device's axis and so you get an error reading saying it cannot track the shot, press enter to reset. The trigger sensitivity can be altered so by keeping it just behind your rifle's muzzle only a couple of inches away from the edge of the barrel and reducing the sensitivity level, you can cut out false triggers. When mounted on a bench using the optional purchase bench stand, my experience of others using this placement is that the audible trigger mechanism doesn't pick up on moderated rifles even when set to maximum sensitivity. This set-up may need a tripod allowing the device to be placed closer to the muzzle. There is an alternative trigger method, but it doesn't seem to be as reliable.

On the original question re the MagnetoSpeed, I have seen the occasional rifle which gets away with little POI shift and no group changes - but I've yet to enjoy this myself having used all three main variants of the device during its life on maybe a dozen or so rifles. I have a shot 100 yard target somewhere that illustrates this graphically firing 15 rounds of the same 6.5-284 load in three 5-round groups. Fitting the bayo' on raised the POI around three-quarters MOA and moved it around half-MOA to one side. (Direction of change depends on the bayo' position in relation to the muzzle as it deflects exiting gasses which in turn slightly deflect the bullet.) Much more the the point, two 5-round groups shot with it off were in the 0.2 to 0.3 inch range in near perfect one-hole round patterns; with the bayo' on, the group was vertically strung and opened to somewhere between half and three quarter inch.

I have also had it the other way round with a series of test groups of a powder / bullet in 7mm-08 all producing really tight three-round groups. Take the bayo' off and the combination simply wouldn't perform with any charge weight. Not too surprising - if it weren't so, people making and selling barrel tuners would be in breach of the Trades Descriptions Act! I should also say, I'm talking heavy barrel match rifles, some with pretty stiff actions like the Barnard Model P fully Devcon bedded, so no skinny whippy barrel sporters that will presumably be more heavily affected.

So, I soon adopted the practice of load five or six rounds of everything new, use 1 shot per charge weight for a pressure / velocity test; then shoot the remainder in each batch for group. What I have found too is that shooting anything up to 10 or 12 velocity-finding shots over a large range of charges (2gn common, occasionally 3) at a single aiming mark, having the bayo' on seems to smooth POI and grouping out - sometimes the whole lot will go into a half-MOA group. What this has done for me is to overcome my past scepticism of the value of adjustable barrel tuners - my next rebarrel will have one installed to see how it works out.

I should say that I am still a fan of the MagnetoSpeed - a huge step forwards over optical devices. However, the Labradar is better still, but it is of course considerably more expensive, and you must either have mains power on the firing point or power it with a high-capacity power pack for anything other than short sessions. The device eats batteries, even if switching it off or putting it into stand-by mode for breaks in shooting.