VarmLR

There's a better and slightly cheaper alternative to acf, Chaz,  calledXCP Professional Rust Blocker. In tests, it outperforms just about anything else on the market for rust prevention and is safe to use on firearms.  I use it for liberally coating the underside of my SUV to prevent our winter salt laden roads corroding the sub frame and suspension arms.  I've found that on vehicles, you can get away with one aplicatrion every 3 to 4 months and it keeps things minty.  Around £14 a can I think.  ACF50 I used on my bikes and firearms until I discovered XCP.  Don't use it in the bore though!

It seems to be fine Chaz.  I keep the gun cabinet liberally stocked with silicon bags and use acf50 to wipe surfaces down before putting away.  My mag bluing has worn at contact points but that's pretty normal for most metal mags so not a concern.  Barrel is fine as is action and bore.

Never experienced any signs of rust on any of my Tikkas, be that blued or stainless.  I do look after them though and they're cleaned and oiled before being put away every single use.  Been out in some pretty awful downpours with them too.  ACF50 or similar might be the answer for those who do experience issues.

The thread drift is what it is.  Generally,  you tend to get what you pay for with bullets and I wouldn't entertain using S&B for long range use...not due to any snobbery...more because the logic (as I see it anyway) is why go to the lengths needed for consistency and low ES/good grouping at long range only to compromise any competitive (or non-competitive) edge by using bullets which are not manufactured to the same tolerance standards as competitors nor when better BC bullets exist.  The bullet you may have missed which doesn't break the bank is Lapuas excellent 139 Lapua Scenar.  Cheaper than the Normas, way cheaper than the Hornady match bullets and something of a benchmark for some years in 6.5.  That's the best answer that I can offer.

5 hours ago, GT3_richy said:

I believe Mr Varm has a Tik Tac, so its 24" (well 600mm, so just under).

Yes, Tic-Tac with 24 inch

I use 44gr RS62 behind a 139 scenar for 2700fps in SRP brass.

For fox, I'd recommend the  SSTs, for gong bashing, the 139 scenars for all ranges to 1000 yds or slightly more.  Just PM'd you...we'll have to catch up soon!

What does your local RFD stock?

HPS-TR....they have a fair few in stock.

Your regime sounds fine, although it might pay to check case capacities in case you have some that are throwing ES out;  I'd also be tempted to batch by OA case length. I try and keep mine all within the range 1.906 o 1.910 after FL sizing.  If you've done all of that and are confident that charges are accurate, then swapping out primers would seem the next logical step.

Good groups but you'll want to firm up ES/SD if stretching legs on distance.  Perhaps try different primers?  I had very reasonable results with Murom Magnum KVB-223M (avoid the standard ones...cup thickness is insufficient).  Remington 7.5s or BR4s also worth a shout.

Thinking a little more on it, you still don't have too many rounds down that new barrel.  My experience with my own TAC was that it took between 300 and 400 rounds before things started getting more consistent.  Also, are you batching your brass and what is your procedure for brass prep?

Good data froggy.  That 44gr load seems to be a universally respectable load for SRP brass and the 139 scenar.  My current velocities match yours almost exactly from the same rifle (my velocities increased with around 400 rounds down the tube).  My last two outings have shown averages of 2703 and 2707fps from two 10 shot strings with ES around 15 (my brass prep to blame) and SD of 10, but that will come down with a little more care.  Accuracy is pretty acceptable.  Your data matches mine and confirms that RS62 (and 50 for that matter) is exceptionally linear wrt charge/velocity, exhibiting none of the spikes that Viht powders tend to IME.

45gr is quite a compressed load in my rifle at 30 thou jump.  Not sure the extra powder is worthwhile as for both the 44 and 45gr loads I found little difference in grouping at 900m. (probably more me than the load) so I stick with the lower load to be a little kinder on the barrel.

The group below was shot using 43.9gr....I have found that to consistently give the best groups and low ES of all my loads across a fairly wide temperature range. the 0.25moa is pretty typical of what I am getting (usually 5 shot but the picture shows a 4 shot group...for some odd reason I can't remember!).

From all of my load development to date, if you plotted a graph of load increment V's velocity, the N140/N150 powders are relatively linear lower in the load range but once past half-way and approaching 3/4 max they tend to curve upwards with some the biggest jumps near the top of the load range, exactly what you don't want if the powders are also temperature sensitive.  My own experience of them is that they are.

RS50/62 (the only RS powders I've so far used) both show a remarkably linear increase on load V's velocity without the same big spikes towards max loads.  Coupled with their relative lack of temperature sensitivity this makes them very consistent and stable powders which makes load development much easier and less fraught at the extremes, although I generally try and avoid loads right at the top end of what is safe, preferring to work in the range of max minus 2 to 5%.

As a matter of fact, I did and found (much as expected) that it wasn't at all that temperature sensitive.

I took the exact same load tested at 24 degrees ambient (although powder temp was higher as the bullets had time to cook a little in the sun) which delivered a shade over 2700 fps from 44gr.

I re-tested at 20 degrees (a little under) and this time the rounds were kept in the shade and fed one at a time into the rifle.  The average from 6 shots was exactly 2700fps, so pretty conclusively it is the barrel that has speeded up for the first 500 rounds down the tube and has now stabilised at this velocity for this load.  My very first firings from it were considerably lower at 2633fps (new brass) and 2655fps (1F, 150 rounds down the barrel) to now where I have 500 rounds fired.  There has been no change in velocity from 400 to 500 rounds and for an ambient temperature range of about 6 or 7 degrees.  No change in 100 yd groups (still close on 1/4 moa for 5 shots).  ES rose slightly with temperature, and rose a little more than SD, but to be fair, I hadn;t batched the last lot of brass, just cleaned, annealed and loaded so it wasn't a fair conparison with earlier outings (my 24 degree ES/SD rose from single figure to ES 33(!!!) but SD was around 10.  I'm usually not happy unless both are single figure, so next time out I'll be far more careful with brass prep.  

The ES/SD of my 129gr loads were much tighter for the same conditions, coming in at ES6, SD4.

The same cannot be said of my Viht rounds which exhibit far greater changes in velocity with temperature, especially for anything north of a moderately warm load (pardon the pun).

I think there's your answer.  You're not on a node and you'll find that 1F brass, that load of 44.3gr on LR 1F brass may be well into high pressure territory and most definitely not a load I would want to start at.   I would strongly advise starting lower, at 41.5gr RS62 in LR primer brass and working up to say 43.5.  You'll find several nodes in that range.  43.5 should be giving you 2800fps or close to.  A chap a few weeks ago was firing 43gr with RS62 and 139 Scenars from his 24 inch barrel and achieving very close to that.

That must have been disappointing for you ezmobile and such things can be perplexing but sometimes the causes are thankfully not too hard to track down.  I'd start (as above) with the obvious things.  Action screw torque, scope rings/scope, brass prep and consistency etc etc.  When this has happened with me it has usually been down to one specific issue.  Also,  to state the blindingly obvious, what were your load development results initially?  You mention a load of 44.3gr behind the Nostlers (SRP brass or LRP brass???)...in SRP brass this would seem in the right ball-park but sounds quite a stiff load for the LRP brass.  

I think that my rifle's throat is quite a lot longer than that Mark at a COAL of 2.872" to lands with the 139gr Scenar.

What COAL are you using Mark? It's a very long bullet, so with SR brass, to avoid crunching down on powder charges, I seat out a little to give as much space as I can without getting too close to the lands. In my rifle, the COAL is 2.842" for a .030" jump and I get no compression but am probably very close to 100% fill ratio.  It just seems to be a sensible compromise.  I have loaded to 44.6gr but that was a compressed load. It still didn't hit the magic 2800fps figure though it came close to it.

I will be switching to LR brass when this batch is done.  I think that the promise of greater velocity for a more economical load seems sensible and now that decent quality LR brass is available, getting into double figure reloads might be possible. 

On 2/16/2018 at 11:49 AM, phaedra1106uk said:

Velocities were about 100fps lower than Vihts published data for the 139 Scenar (nearest weight).  Laurie Holland has a few posts on here about the effects of small primer brass on velocities which are well worth a read (as is everything else he posts!!).

The Nosler 140s came out at a 5 shot average of 2496fps, I've got some Murom KVB223-M magnum primers being picked up for me at the Shooting Show so I'll start load development again with those and chrono a few loads next week if I get the chance.

Seating depth with the Nosler 140s is 2.317" and 2.327" to give a 30 or 20 thou" jump, measured to the ogive, COAL is 2.815" or 2.825"

I don't know if you've considered RS62, but I'm managing considerably higher velocities than that behind 139 Scenars, albeit for a considerably higher load!  Were you experiencing pressure signs if loading up higher than 35gr using N150?  35.5 seems to be quite a light load compared with RS62 loads.  I also find velocities about 100fps down in LR brass.

Thanks guys.

@Catch-22:  I see your point RE burn rate but I wanted to settle on one powder for 123 to 140grn for the 6.5.  Velocity comparisons have to account for SR brass, which in my own experience tends through lower ignition energy to result in considerably less velocity than its LR stablemate load.  Typically, I am finding 100fps difference between them for the higher velocity plateaus.  Bear in mind the 24 inch barrel and that RS62 is single base, and in LR cases, it should easily manage 2900 to 3000 fps from that barrel, whereas the 139s I reckon will struggle to get much above 2800fps, but then again, they don't need to...they're a slippery bullet!  I favour accuracy over outright speed but appreciate that the faster it's pushed, the lower the wind affect.  For my purposes, RS62 seems ideal.  It's stable, linear and pushes all the bullets I use to reasonable velocities. I'm not a fan of double base powders but have little doubt that I'd see considerable gains using RS60 perhaps.  I thought that RS50 might be a little too fast in CM, even for the 123gr so haven't tried it (I am happy to be corrected on this though) but saying that I know a few people using N150 for the 123gr bullets so maybe it might be worth a try.

@MarkR  Yes, 44gr RS62 seems universally popular as a sweet spot load behind the 139s (equally, 42.5 to 43gr in LR brass does the same thing) in SR brass.  I arrived at it using OCW and haven't tried pushing the 139 harder with a mildly compressed load when the 44gr seems to shoot so accurately.  I was shooting with a few chaps last who went straight to 44gr in SR brass (perhaps after reading my earlier rambles!) in similar length barrels, and they seem to have had some success with that load.

Data from load tests:  (Please bear with me here as the results may be of interest)

Satterlee loads were started at 40gr RS62 and loaded in 0.5gr intervals to 44.5, then in 0.3 intervals to 45.4gr.  Based on SR loads needing to be between 0.6 to 1.0gr m,ore than LR to obtain similar velocities and pressures, I could have loaded on up to 46gr but chose to cut off with a margin of safety.

Only two plateaus were witnessed.  One at the lower end between 40 and 41 gr where velocities were all within 10fps averaging 2488fps -6/+8 fps.

The other was between 44.8 and 45.1 where loads were duplicates at 2807fps.

Interestingly, these did not correspond well to the OCW tests which I expected they would, so either my brass prep was to blame or my load divisions were too crude (perhaps the truth lays somewhere in between).

OCW showed the lowest ES at 43.5gr for 2684fps and an ES of 6.

OCW groups favoured the two highest loads which fell in the same place and were touching holes.  These were at 44.5gr and 45gr, with the lowest ES a disappointing 17, yet the velocity averages for the two were 33fps apart.  Average gain in velocity with RS62 was remarkably consistent and linear...MUCH more so than any Vhit powder I've used which tended to bunch the highest gains to perhaps the last 25% of the load ladder and have a tendency to spike, especially in hot weather.

RS62 showed a remarkably linear result of between 78 and 86fps/gr increase from lowest to highest loads.

What else was noted was that the temperature sensitivity was much better than inferred from the previous outing using the 139gr where I concluded that in 24 degree heat the veloicity increase over initial loads was down to temperature.  Well, it wasn't as I duplicated the 24 degree velocities tody when the temperature was some 6 degrees down, delivering almost identical velocities.  This then does point to the barrel gaining speed with its first 400 rounds and thankfully shows that RS62 is far LESS temperature sensitive than first thought.  I have enough data now to share the temperature factor which across a broad range of temperatures indicates at 1.3%.

The conclusion here using 123gr Scenars is that unless pushed harder in SR brass towards 2900fps which looks like being a stiff load of 46gr, then it has little, if any advantage over the 139gr shot at 2700fps.

For my loads, I have the following terminal velocities given as calibrated to measured velocities and BCs:

139 Scenar, G7BC 0.291, MV 2700fps (18 degrees C), terminal velocity 1000 yards = 1379fps

123 Scenar, G7BC 0.266, MV 2807fps (18 degrees C), terminal velocity 1000 yards = 1347.2fps

To match the 139gr based on the load/velocity relationship would require a load of approx 45.5gr.

Conclusions:

I can't really see the point of shooting the 123gr simply to "match" the 139gr and using more powder in doing so.

I can see the point of a stiffer load of perhaps 46gr to get to a shade under 2900fps (24 inch barrel. SR primer) because the 139gr is already approaching the max load and would be quite compressed with any more powder underneath it.

So,  the conclusions are that if you use a longer target barrel, and consider it a consumable, then the extra case capacity behind the 123 Scenar makes it possible the target shooters choice with a stiff load under it, as I can see this easily achieving 3000 fps+ in a 24 inch tube for a LR primer load of around 45gr RS62.

If you shoot a 22 or 24 inch barrel, you are probably better off sticking to the 139 Scenar becvause it hangs onto its velocity well enough to pip its lighter brother to the post for a more economical load.

I now have 200 123gr scenars to shoot my way through before returning to the 139!

I will be trying the 123gr Scenar in the CM, and as I have stocks of RS62 I was going to use that with a start load of around 40gr and a max load with SR primers somewhere between 45 and 46gr.

I cannot find out much about this load combination but do note that IMR H4451 Enduron and H4530 use very similar charge weights to RS62, and starting load for those powders and the 123gr is around 40gr, max just under 45 (LR brass).

I'll post the results here.  This time round I'll be comparing Satterlee V's OCW to see the correlation I get (in theory, OCW should yield a node at a similar charge weight to one of the Satterlee derived plateau nodes).

I have noted that COAL for the 123gr when seated to lands is quite a bit longer than that of the 139gr (2.887" V's 2.872") hinting towards a sleeker profile.

I measured a batch of 10 of the 123gr bullets and obtained an average bullet length of 1.306" with an ES of .009". This seems a bit out compared with the JBM published length of 1.298" and is as you'd expect a little shorter than the 1.364" of the 139 Scenar.

G7 BC of the 123gr is given as 0.266 V's 0.291 for the 139gr.  Velocity being aimed for (123gr) as a bullet to cover all ranges to 1000yds is between 2850 and 2900 fps so it will be interesting to see what this bullet/powder combination delivers.

Hi ezmobile

I use a 30 thou jump for mine as I saw no real benefit in chasing the lands and only potential problems.  For my barrel this equates to a COAL of 2.842" for my TAC A1.  I think I read somewhere that SAAMI optimum COAL was 2.820" so mine could be throated quite long.

I FL resize all my brass (using Redding dies) as I see no benefit in neck sizing and only issues on the horizon as they'll eventually need FL resized anyway.  I anneal each firing and try to keep things as consistent load to load as I can.  I also use a Lee factory crimp die but only to give a very slight crimp to try and uniform neck tension for each round.  I have found differences between several batches of muroms I used, more with SR standard which I no longer use.  For 6.5CM I use either KVB-223M or CCI-450 (being tried for my next batch to see if there is any improvement in MVs and SDs over the KVB-M primers).

Yes, well spotted. It should read 44.6.   Any more is getting into compressed loads