I forgot that the Peterson brass I have is LRP; I was also shooting Lupua SRP today ( 6mm Creedmoor) Fed 210 for Peterson and CCI 450 for Lupua. The same load LRP was 50FPS faster and a tighter group. I read some folks weren't too happy with the CCI 450( These were old primers, too) primer. I have a bunch of CCI141, any suggestions on another primer to try?
New Peterson brass
- Thread starter Ironworker
- Start date
The Peterson is lighter; because it's LRP rather than SRP. Scrounging around in the primer box, I found a 300 Remington 7 1/2 Benchrest.
HTSmith
Silver $$ Contributor
What this feller said. And fwiw I've fired thousands of CCI 450's with good to excellent results.
6.5 forever
Silver $$ Contributor
Maybe more to do with case volume than primer difference. I have not witnessed a primer make that much difference.
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SRP ignition gives very different results from LRP in this size of case, powder charge type and weight. This is a normal expectation among 308 Win Lapua Palma SRP brass users for instance and charges are adjusted upwards almost as a matter of course.
Far from 50 fps being an abnormal reduction, it's pretty common in this size of cartridge, and I've seen larger MV reductions in some comparisons. SRP charges usually have to be adjusted up by 0.5 to 1.5gn on an LRP to SRP switch in Creedmoor / 308 Win size cases depending on charge weights and the powder burn-rate and/or how easily it ignites.
The cause is that SR primers are far less aggressive than LR equivalents and the volumes / weights of super-heated gas and solid ejecta that they force into the powder column is much reduced. If ambient temperatures are low and the case-body brass and powder kernels cold, they have much less energy available to heat those items up and reach the temperatures that give consistent ignition. That's why Lapua advises against this type of brass in cold weather hunting. If your testing was done in anywhere close to freezing point never mind below, this may also have affected your results. Lapua and Peterson SRP cases also come with smaller diameter flash-holes than LRP equivalents - 1.5mm vs 2mm - and this affects ignition too. (It improves consistency reducing MV spreads where it works well, but can make a poorer job of igniting the powder column in non-optimal situations.) Finally, SRP ignition doesn't work at all well with some powders. I couldn't get it to work in 308 with Hodgdon CFE-223 for instance - two complete misfires and almost every other round a mild hangfire.
As an example of MV reduction, have a look at:
http://www.targetshooter.co.uk/?p=2621
at a table at the very end of the piece on 308 Win / 167gn Scenar / Viht N150 LRP and SRP MVs fired side by side in a single session, both in Lapua brass with very close fireformed water capacities.
The final point to note is that not only does SRP brass require heavier charges, but it has very strong case-heads due to the primer pocket being smaller and removing less metal from a key pressure-bearing area of the case. As a result a full-pressure charge worked up in an SRP case should never be transferred as is to LRP cases even of the same make. It is essential to drop charges and work up again.
Far from 50 fps being an abnormal reduction, it's pretty common in this size of cartridge, and I've seen larger MV reductions in some comparisons. SRP charges usually have to be adjusted up by 0.5 to 1.5gn on an LRP to SRP switch in Creedmoor / 308 Win size cases depending on charge weights and the powder burn-rate and/or how easily it ignites.
The cause is that SR primers are far less aggressive than LR equivalents and the volumes / weights of super-heated gas and solid ejecta that they force into the powder column is much reduced. If ambient temperatures are low and the case-body brass and powder kernels cold, they have much less energy available to heat those items up and reach the temperatures that give consistent ignition. That's why Lapua advises against this type of brass in cold weather hunting. If your testing was done in anywhere close to freezing point never mind below, this may also have affected your results. Lapua and Peterson SRP cases also come with smaller diameter flash-holes than LRP equivalents - 1.5mm vs 2mm - and this affects ignition too. (It improves consistency reducing MV spreads where it works well, but can make a poorer job of igniting the powder column in non-optimal situations.) Finally, SRP ignition doesn't work at all well with some powders. I couldn't get it to work in 308 with Hodgdon CFE-223 for instance - two complete misfires and almost every other round a mild hangfire.
As an example of MV reduction, have a look at:
http://www.targetshooter.co.uk/?p=2621
at a table at the very end of the piece on 308 Win / 167gn Scenar / Viht N150 LRP and SRP MVs fired side by side in a single session, both in Lapua brass with very close fireformed water capacities.
The final point to note is that not only does SRP brass require heavier charges, but it has very strong case-heads due to the primer pocket being smaller and removing less metal from a key pressure-bearing area of the case. As a result a full-pressure charge worked up in an SRP case should never be transferred as is to LRP cases even of the same make. It is essential to drop charges and work up again.
CCI 450 worked very good in my 6BRX as well. No issues at all.
Thanks I'm burning N555 and H4350 . 45 degrees temps in Nevada desert yesterday. What about WW SRP and Rem 7 1/2 compared to CCI 450 ?
I tried N555 in both types of brass in 7mm-08 with 160gn TMKs, and got markedly better results from LRP ignition. A one-off comparison, so may not be significant. (This was a tangential sortie in a series of tests looking at alternative powders to H4350, one of many powders we no longer receive in the UK.) The LRP primer used was the old Russian PMC Large Rifle Magnum (KVB-7M), which despite its 'magnum' designation is a very mild number and works very well with c.45-50gn charges of H4350, N160, N165 and similar.
http://www.targetshooter.co.uk/?p=3683
45-deg F shouldn't cause any problems.
With primers models, you can only suck it and see if any works better or worse than the others in any combination and in your own rifle. All three are excellent primers and perform well. The only caveat is that the Winchester WSR has a thinner brass cup than the other two (0.021" vs 0.025") making it a bit weaker and more prone to 'crater' or 'blank' under high pressures. Having used the Rem 7 1/2BR in many cartridges for over 25 years, I'm very fond of this model and generally had excellent results from it, but there is nothing at all wrong with the CCI-450 you're using now.
Here's what I got in 308 Win SRP and Viht N150 with a range of SR primers:
http://www.targetshooter.co.uk/?p=2662
However, those results may not be replicated in 6mm Creedmoor with N555.
I did the same type of experiment with my 6.5 Creedmoor, using SRP cases vs the LRP cases, same charge weight and bullet weight, everything was the same except the primer size, The Winchester LRP out preformed the CCI450 SMRP, from my test on this I will not use the CCI 450 magnum primer or the SRP brass again unless I have no other choice, I was also running the 147gn ELDM bullets with 41gns of RL16, that said, things may change if I seat the bullets deeper into the case on the SRP brass! JMO.
Ned Ludd
Silver $$ Contributor
Large rifle primers generally have much greater brisance than do their SRP counterparts. That's the main reason that SRPs are generally not recommended for use in .308 Win loads to be fired in cold temps, below about 20 degrees F or so, because they may not provide reliable ignition. The large rifle primer has more priming compound, greater brisance, and therefore generates higher velocity from the same charge weight. There could also be a difference in the flashhole diameter that might be a contributing factor, but I am not familiar with the flashhole diameters used by various manufacturers in 6 mm Creedmoor brass. Lapua uses the smaller .062" flashhole in their .308 Win SRP brass, whereas Alpha Munitions .308 Win SRP brass uses the larger .080" flashhole. I don't know with certainty what diameter flashhole Peterson LRP brass uses, so it could be either one.
Likewise, the better precision obtained from the Peterson LRP brass may simply be because the 50 fps greater velocity produced a more well-tuned load. In order to make a fair comparison of the two brands of brass, it would be necessary to create two completely independent and optimally-tuned loads, one with Fed 210s in Peterson brass and one with CCI 450s in Lapua brass. Anything else is simply not comparing apples to apples. It would not surprise me if the Lapua/CCI 450 load were increased to a similar velocity (via greater charge weight) as was obtained with the Peterson/Fed 210 load that the results might be more similar in terms of precision. A 50 fps decrease in velocity could be more than enough to put the Lapua/CCI 450 load out of the "sweet spot".
Likewise, the better precision obtained from the Peterson LRP brass may simply be because the 50 fps greater velocity produced a more well-tuned load. In order to make a fair comparison of the two brands of brass, it would be necessary to create two completely independent and optimally-tuned loads, one with Fed 210s in Peterson brass and one with CCI 450s in Lapua brass. Anything else is simply not comparing apples to apples. It would not surprise me if the Lapua/CCI 450 load were increased to a similar velocity (via greater charge weight) as was obtained with the Peterson/Fed 210 load that the results might be more similar in terms of precision. A 50 fps decrease in velocity could be more than enough to put the Lapua/CCI 450 load out of the "sweet spot".
Thank you very much; very helpful.
I just received a shipment of 100 Alpha Munitions SRP 6mm Creed. So now I'm asking myself why did I ever want SRP brass. My charge of N555 is 43.3 in Lupua brass for an average velocity of 3,075. The LRP Peterson brass shot better; I can increase charges by .03 increments.
Are CCI 450 the hottest SRP
I'll refer you again to my feature in Target Sports magazine re small rifle primer performance, the second link in post #9.
MV is a good guide to primer aggressiveness - higher the MV, 'Hotter' the primer with all other components the same.
What I found is that there is a very small performance range in this respect compared to large rifle primers. With such a small range, production lot variance may be as important as primer model as they can vary significantly lot to lot. If you look at Table 1, the CCI-450 produced MVs slightly below the mid-point of the range I saw.
MV is a good guide to primer aggressiveness - higher the MV, 'Hotter' the primer with all other components the same.
What I found is that there is a very small performance range in this respect compared to large rifle primers. With such a small range, production lot variance may be as important as primer model as they can vary significantly lot to lot. If you look at Table 1, the CCI-450 produced MVs slightly below the mid-point of the range I saw.
6.5 forever
Silver $$ Contributor
I believe so. But that may vary slightly with different lots.
I believe for a proper test you would need to include Lapua brass as well a alpha, in this thread I see a lot of reference to Peterson brass, I can honestly say I bought 50 pieces of peterson dasher brass and after significant tests with it I threw it away went back to Lapua and alpha, I believe other people have done the same thing, jmtcw……
What problems were you having with Peterson
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