Load testing LRP vs SRP with terrible results

[6Creed73]

So, what did the targets say?

It was a terrible day for analyzing groups. It was windy with shifting directions. Even my loads that always produce solid groups were all over the place. Only thing I could go off of was the chrono.

 

[STS]

I have done a fair amount of testing with SRP Lapua 6mm CM brass necked down to .22 CM. I have to say that I disagree with the absolute recommendations that SRP will not work with case capacities in the 40+ grain range. I load up to 46.x grains of RL 26 and N160 in that case, with a CCI 450 and a 69 grain bullet, and have excellent ES/SD numbers. I have also tested the hypothesis that SRP will not work at low ambient temperatures. This winter I tested the above load AT 25 BELOW ZERO and still had excellent ES/SD and groups out to 400 meters. I can tell you one thing that will not work in a cold environment, and that is a Fed. 205 primer. They will not reliably light off those charges at low temps. I had the only hang fire I've ever experienced with a .22x47Lapua with a Fed. 205 at 18 below zero.

 

[Bill Norris]

I have done a fair amount of testing with SRP Lapua 6mm CM brass necked down to .22 CM. I have to say that I disagree with the absolute recommendations that SRP will not work with case capacities in the 40+ grain range. I load up to 46.x grains of RL 26 and N160 in that case, with a CCI 450 and a 69 grain bullet, and have excellent ES/SD numbers. I have also tested the hypothesis that SRP will not work at low ambient temperatures. This winter I tested the above load AT 25 BELOW ZERO and still had excellent ES/SD and groups out to 400 meters. I can tell you one thing that will not work in a cold environment, and that is a Fed. 205 primer. They will not reliably light off those charges at low temps. I had the only hang fire I've ever experienced with a .22x47Lapua with a Fed. 205 at 18 below zero.

Have to agree. I have 50 pcs. of Peterson SRP brass for my 40X 260AI that I load from 44.0 to 45.5 gr. of H-4350 & up to 47.5 gr. of H-4831sc so far with 130 to 140 gr. bullets and accuracy is as good as my Lapua brass. I have had no issues with hang-fires at all. I mostly use CCI BR4 and CCI 450 primers in these loads.

 

[46and2]

Both the LRP and SRP were once fired in my chamber and neck sized. I got lucky and found 1000 CCI 450's locally and will be picking them up tomorrow. Then, like you mentioned, I'll load some up to do some ladder testing.

Your problem just might be the neck sizing.
Try Full Length sizing, bumping the shoulders back. 002 just to see what happens.

I've tested this a few times, FL sizing is more accurate for me.

 

[6Creed73]

Your problem just might be the neck sizing.
Try Full Length sizing, bumping the shoulders back. 002 just to see what happens.

I've tested this a few times, FL sizing is more accurate for me.

I neck size for two firings, then FL size...been doing it for years with great results. If it was the neck sizing I'd think it would affect my established loads as well.

Also, both my neck sized cases and FL sized cases have the same neck tension.

 

[Raptor]

I had the same Issue with my 6 Creedmoor. SRPs sucked and that was in Lapua brass vs LRP Hornady brass. LRPs shot better......

 

[1shot]

I will politely dis-agree with the notion that anything above 36 gr. won't work.
I run 42-44 gr. of N-140, N-150 Varget or RL-15.5 under a 200 gr. bullet in my 308 with SRP CCI#450's with no problems at all. single digit ES and groups in the .3-.4 range in my FT-R rifle.
I hope this helps,

Lloyd

 

[ckaberna]

I have done a fair amount of testing with SRP Lapua 6mm CM brass necked down to .22 CM. I have to say that I disagree with the absolute recommendations that SRP will not work with case capacities in the 40+ grain range. I load up to 46.x grains of RL 26 and N160 in that case, with a CCI 450 and a 69 grain bullet, and have excellent ES/SD numbers. I have also tested the hypothesis that SRP will not work at low ambient temperatures. This winter I tested the above load AT 25 BELOW ZERO and still had excellent ES/SD and groups out to 400 meters. I can tell you one thing that will not work in a cold environment, and that is a Fed. 205 primer. They will not reliably light off those charges at low temps. I had the only hang fire I've ever experienced with a .22x47Lapua with a Fed. 205 at 18 below zero.

The 205’s should work for me, if it gets to 18f below I won’t be pulling any trigger. At least I hope not, I’m a “fair weather” type shooter. Lol

 

[JFrank]

I will politely dis-agree with the notion that anything above 36 gr. won't work.
I run 42-44 gr. of N-140, N-150 Varget or RL-15.5 under a 200 gr. bullet in my 308 with SRP CCI#450's with no problems at all. single digit ES and groups in the .3-.4 range in my FT-R rifle.
I hope this helps,

Lloyd

I was thinking along the same lines, last I heard 308 Palma brass is SRP and they shoot pretty good.

 

[Dusty Stevens]

David tubb did a study on srp vs lrp on the 6xc and he stuck with the lrp. Maybe he will chime in with an actual study + experience more than my experience with the long range 243s back in the day. @DTubb

 

[STS]

I'll add another data point to the discussion. I ran out of the lot of CCI 450's that I was using in one of my 22 CM predator rifles and wanted to do a bit of a tune up on the rifle anyhow, so I did a range trip today. The rifle details are, tuned up 700 that has been optimized for ignition, Krieger 8T 21 inch 4 groove suppressed, N-160 powder 46.x grains, Lapua 6mm CM brass formed to 22, CCI 450 primer and a 69 grain Lapua Scenar. Before somebody gets their undies in a wad, I realize this is a small data set and is not a 10, 20 or 100 round test. However, I believe it is illustrative of the main question that this thread is about. The data is as follows.....
Velocities were...... 3598, 3600, 3600, 3605 and 3616
ES=18
SD= 6
The temp was 47 degrees. Those chronograph numbers are pretty much what I see with that rifle over time.
In my experience, if you don't have acceptable ES/SD numbers with CCI 450's, it may very well not be related to the primer at all. There may be a skunk somewhere else in the rifle/load.