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Small vs. large primers with 22 Creedmoor

Someone posted on Bench Rest Central years ago that SRPs didn't work so well if the charge weight was very much over 40 grains. I imagine that a small rifle magnum primer would fix that. The only advantage to SRP would be the ability to handle more pressure. If you are not going to exceed what a LRP will handle, it seems like not worth iffy ignition.
 
Someone posted on Bench Rest Central years ago that SRPs didn't work so well if the charge weight was very much over 40 grains. I imagine that a small rifle magnum primer would fix that. The only advantage to SRP would be the ability to handle more pressure. If you are not going to exceed what a LRP will handle, it seems like not worth iffy ignition.
The CCI-450M SRP primer works well in my 260AI with up to 48.0 gr. of H-4831 in Peterson brass. But, I do not shoot in colder weather. I have seen better ES/SD #s with the SRP than the LRP.
 
Pressure tolerance better with SRP but more likely to have ignition issues with cold weather or ball powder. Another symptom is increased ES/SD from inconsistent ignition.
I can’t answer on a 22 creedmoor but on my 6 creedmoor I use Lapua brass CCI 450’s 115 Berger’s and a full case of RL 26. I have single digit sd and I’ve shot in below zero with it and have never had a hang fire or any ignition problems yet. Hopefully I didn’t just jinx myself
Wayne
 
In my case the potential incremental gain in case life or pressure tolerance wasn't worth finding out if there would be an issue. The rifle is fundamentally a hunting rifle and used in inclement weather conditions (temps down below zero as well). Also I had been experimenting with Superformance powder - charge weights up to the mid-40's with a ball powder seemed like a higher potential for an ignition problem.

That being said the CCI magnum primers (either #41 or 450) have in other cartridges seemed to be the hottest and most reliable if you do indeed end up going SRP.
 
The more you shoot these things the more you learn about them. Or at least you should learn. I have shot about 1800 rounds through two different .22 CM barrels. I've learned a couple of things that are often thought to be fact, that turn out not to be true. One of those things is that in cold temperatures, small rifle primers will result in hang fires and poor ES/SD numbers. I live in southwest Montana and spend quite a bit of time predator hunting each winter. It's not uncommon to hunt in weather that is as much as 20 below zero. With CCI 450 primers, I have never had a hang fire. Two years ago it was 38 below zero here one morning and I decided to do a test to see what the rifle would do at really cold temperatures. By the time I got going, and made it to the range, it had warmed up the 25 below. I set up my rest and rear bag, chronograph, and set the rifle and ammo on the bench, then retreated to the pickup and waited 30 minutes. Every shot went off without any hagnfires. The velocity was slower than normal, but the SD was single digits. The more I investigate this type of thing, the more convinced I am that hang fires, and failure to fires, are action ignition performance related rather than primer performance. I can also say from testing that I wouldn't count on the same performance out of Federal 205 primers at those temperatures. You will get hang fires from those, ask me how I know. :D
 
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Great question. I use Petersen LRP and SRP brass for my 22 Creedmoor Match rifle. The hang fire issue is real with the SRP brass and smaller charge weights. I’ve run 34g of H380 and 31.5g Varget under 77’s and have had hangfires with both, despite the fact that both loads work Phoenominally with LRP brass. I’ve used this in blazing hot weather at the Western games last year and the State Championship this past weekend. I will say the hangfire was less in the cold weather than it was in the hot.

SRP brass with full loads of N165 under an 80gr are amazing, and won the 600 yard match last Saturday. I use the SRP for 600 yard ammo mainly as it has less loadings than my LRP.

My go to load of 31.5 of Varget and an 80 SMK shoots very accurate out of both, but I tend to run it with LRP brass to avoid any chance of a Hangfire.

Finally, the LRP brass is a total pain to seat primers in, while SRP brass is much easier. The LRP pockets are wicked tight even after 10 firings.
 
I use CCI 450 and 41 SRP in all of my Creedmoor rifles (22, 6mm, 6.5mm) in AR10 and Bolt platforms. I can achieve single digit SD's on each of my loads and do not experience hangfires. Down to -10 degrees is low as I've utilized.
 
I wish someone, (Rocketvapor where are you) would do a primer brisance test, attaching a number for the value of each primer in a chart we could compare them with. I would do this myself, but --- Ah hell, I'm just too lazy and dumb. jd
 

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