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RS52 and 308W load data

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Anyone loading this combo able to suggest a reasonable starting charge weight please? barrel is 20" 1:12, using new Lapua brass, 155gr and 168gr Amax, CCI BR2s. CBTO 2.222 which is a nats over 20 thou off lands.

 

Cheers,

Rich

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Anyone loading this combo able to suggest a reasonable starting charge weight please? barrel is 20" 1:12, using new Lapua brass, 155gr and 168gr Amax, CCI BR2s. CBTO 2.222 which is a nats over 20 thou off lands.

 

Cheers,

Rich

Don't Reload Swiss have data on their website for the main bullet weights in 308,minimumum to maximum should be a ggod guide.

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The closest they have data for is the Sierra 150gr. Being new to reloading I hoped someone would have real world data I could consider alongside QLs suggestions.

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Rich,OK -best to be careful when new to reolading-indeed always. But makers data can be used for bullets of the same weight (and general design-eg HPBT) evenif not the named make..you'll see there is quite a differnce between the beginning minimum load and the max;so work up from the lower in say .3g increases till pressure sign/or you get good grouping.Then fine tune.

You may have to convert g (grams) to gr (grains)......thus: gx15.432 = grains...

 

So 10.9 g is 168.2 grains,which is one of your bullet weights (and a HPBT)...you can use RS 52 308w data given....

 

(9.7g is 149.7 grains so you could use this data for your 155gr bullets-generally the heavier the bullet,the lighter the powder load,with the same powder-RS52-but starting with the minimum should be OK,with only a 5gr difference in bullet weight-if you don't get another reloaders data...but be aware,rifle differ a bit,sotaake care with any load approaching say a grain under max....stiff bolt lift,flattened primers are pressuresigns...back off.

 

It's unlikely that CBTO will be identical for differnt bullet weights,but not impossible...but all the detail isn't too relevant to getting the basic powder load-really it's bullet weight that matters (given a similar bullet design).But far better to give it than be vague-it might matter more for some things....eg CBTO will vary between differnt same weight bullets from differnt makers as the bullet 'ogive' (curve) won't be identical -if you want more on this length/ogive read Berger Bullets (Litz) article comparing CBTO woth COAL-but don't worry too much about either yet-load to COAL to just fit your magazine,for starters.

But keep asking-it's not rocket science,but you need to get the basics right (just to reassure,commercial ammo is loaded to fit the standard (SAAMI) size magazine....and SAAMI standard chambers (and works ok,maybe not ideal even if the barrels have somewhat differnt 'throats/leades-the gap from chamber to rifling,allowing some COAL-better yet BBTO-vatiation to seeif the rifle has a 'jump' preference...but that's fine tuning,and needs a goodbullet comparator etc-get a few hundred down range before you get into that...a 308 should be good for around 5000 rounds with sensible loads...don't go above book max.....it really will not offer you much extra at all.......so enjoy,safely.

 

 

 

gbal

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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.

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George - thank you - I was mainly looking for 155 A-max data as that's what I'm loading first, my cbto length above was from the 155gr - not touched a 168 as yet :)

 

I did note that the 150gr Sierra was a BTHP, just wasn't sure how much difference the extra 5gr/any difference in length compared to the Amax might make. My mag length is way in excess of where the lands are with the 155gr, so went with 20-25 thou off (using OAL gauge/comparator) as a starting point. I will add the Litz article to my reading list!

 

Laurie - the main reason I asked on here was to find assurance or otherwise regarding QLs RS52 modelling. I will most certainly heed your advice and start at 43gr and see where I am at around 46gr.

 

Thank you both for taking the time to reply, much appreciated. As fun and interesting as reloading is, its quite daunting at the outset! I am most grateful for your input.

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Rich,indeed -it'a hobby in it's own right-pursuable to just basic afe ammo,or seeking optimim performance geared to anindividual rifle (much more work,and probably expense in equipment). Just keep reading good sources-the reloading manuals,and informed experience-none better than Laurie ! BE cautious of individual claims-none of us can actaually measure pressure,and goodness/badness knows what pressures underliesome velocity claims(some might even be accurately measured-that's on a magnetospeed or Lab radar-screen chronos can be less reliable.Measurement is grsreat-so long as it is good measurement.

OK,you also build up some 'guidlines/rules of thumb',but proceed with some caution.Just as an example,the RS book data for RS52 with 9.7 g bullet (150g) gives min of 2.61g to max 3.05 g (which is 40.3 min to 47 max grains....and note we are about in the ball park Laurie gave on the varget base...crucially 46+max.....I wouldn't use any 150g bullet loads to extrapolate to a 185 bullet,but you can see that 150-155 with a bit of caution esp at max seems do-able. AS with ANY load,you are looking carefully for pressure signs (stiffer bolt lift,flattening primers,marked case head-from ej plunger ,etc etc-) and not assuming no such symptoms guarantee safe loads-when present thse symptoms say..."ease of",of course. When you can ,look at the very diminishing ballistic returns that the last fractions of a grain actually offer -it might be worthwhile if you are a top competitor at 1000y,but mostly it's not much (under an inch drop/drift eg for 300y 223 loads)...and you get a small bonus of better barrel life with a little reduction...accuracy is sanity,velocity is vanity ! Enjoy. :-)

g

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Excellent advice from Laurie there Rich. To echo his comments, I've also found the QL predictions are a little out from measured results with RS50. There's something going in in QL which doesn't quite marry up with actual results from RS powders in this burn rate/energy for some reason. In my case in .308 and 175gr bullets, QL predictions were comfortably being exceeded in MV (and therefore likely in pressure too) by between 50 and 80 fps, so I am wary now when looking at QL results for RS powders.

 

Recently, RS were kind enough to provide me with a QL run for my 6.5 CM and various bullets, and where the data enters the purple "high pressure" zone at approx 99% fill ratio with RS62 is where I'll probably draw the line in my load test ladder. So far, I've been finding loads that work well below where higher pressures may be encountered allowing a margin for safety.

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Well the good news is I'm still in one piece after firing the first 24 rounds I've ever made, yay...

 

I loaded 43gr to 47gr. I shot a dozen factory rounds first then my loads. At 46 and 46.5gr the cases looked mint, no marks on the heads and the bolt lift was light and silky still and extraction was effortless. I thought about this thread and decided to leave the 47gr in the box as I didn't want to ruin a good day!

 

Unfortunately I was late leaving home and in the rush managed to leave behind the Magnetospeed and cans (fortunately had ear plugs in the car). I'll load some more of the same and chrono them next week, groups were fairly consistent tbh, very little vertical spread, most were 2 touching and the 3rd a little off. I called about half of them due to moderator mirage or crap trigger work, it was also quite gusty toward the end of the afternoon. I've gotten used to firing my 204 and 223 the last 6 months so the 308's recoil is still a bit of a novelty so I'm sure there's plenty of room for improvement in my non-existent technique.

 

I've emailed RS to see what data they might be able to provide, they seem very pro-QL so I'm intrigued so see what they suggest.

 

Thanks again for the input in this thread, gents all of you.

 

 

 

.accuracy is sanity,velocity is vanity ! Enjoy. :-)

Hah, I've not heard that before. I will try and remember this ;p

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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!

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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.)

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TBH Laurie I don't think I ever got it right! Good scores at 800 but at 900&1000 the vertical came in big time! Launching it at @3060fps my ballistic calculator(shooter) said it would be above transonic just at 1000. However I always needed @2MOA more elevation than the calculator predicted so either the velocity(labradar) or the BC (using litz G7)or something else not quite right.

A little scared to push it any harder so going to try some heavies!

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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.)

I found the same thing with the Berger 155 hybrids, and strangely the same as the SMK Palma bullet #2156. They both perform well after a 0.040" jump.

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Hmmm....chambers,freebore and barrel rifling (and quality) are not cloned,especially between makers.So there will be some intrinsic precision variation in rifles and ammo.

Shooters differ in abilities,so accuracy will have that variable added in.Quite possibly the 'outcome' is not always comparbly described ( is 'very accurate" one moa or... Etc)

 

That said,there do seem to be quite wide reported differences.Shame-if there were not,we'd just have to have one load development per bullet/powder combo,and it would work equally for any rifle.

 

But not neccessarily for every nut behind the butt... :-)

 

gbal

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On 22/10/2017 at 8:50 AM, Webby said:

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!

Hi Webby,

I was wondering if you were any further forward with your testing of heavier bullets in relation to RS52 and QuickLoad. I've just completed a FTR build based on a Savage dual port action with a 32" Bartlien barrel. I'm intending using Berger 185 Juggernaut Target bullets (base to ogive @ 2.293" at 20 thou off with a coal of 2.971") in Lapua Palma cases with CCI BR-4 primers although I may change to Muroms if I can get a hold of some.

I was amazed at how much of a difference it made with the figures produced when altering the burn rate to your 0.5500 and wondered if the same figure still held true with a heavier bullet.

All the Best,

Panda

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It didn't require anywhere near as much adjustment with the heavier bullets. However the bullets I used were not in the quick load database so I used a Berger equivalent and altered the length. (Not very scientific). So I guess that something else is going on in QL with these powders. TBH I hardly use QL anymore as RS52 is my choice powder. I just head to the range with a large spread of weights in test tubes and my lab radar. Load single rounds looking at velocity and primer condition to start with. Then when I am somewhere close I load for group testing. I always hoped that QL would stop me having to load at the range but no such luck! As an aside I am pleased with the muroms even the std kv223 have not given me cratering at very stiff loads however this is prob due to my boldface having a nice small firing pin hole. However at the final F class match last W/E (cold&wet) my 1st cold barrel shot on both days produced a very noticeable click/bang delay. It didn't occur again after that and my overall result of 7th with a 3rd place in one of the 1000yrd comps was very respectable!

 

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I used to use RS52  under Sierra MK's 155's (2156) and RWS cases in my Target rifle with a 32" 1:12 barrel. I needed to get them up to 3000 fps for 1000 yds on Stickledown. The suggested charge according to Quickload was a tad over 48 grains (I think it was 48.3) I did a velocity test and found them to be running way over 3K, plus I had pressure signs and a hard bolt lift. 

So, to totally back up what Laurie says, don't trust QL too much!  I eventually wound it back to exactly 46 grains before finding the 3000 fps I was looking for, but once there I found it to be a very effective powder for my use.

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I took this threads suggestions on board :)

I loaded some 165 Gamekings last week. From recollection QL suggested 45gr of RS52 would be 2520fps @ 44K, changing the burn rate to 0.5500 gave 2645 @ 53K - at the range 45gr gave 2657.

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