I'm going to get a 6.5mm barrel for my AX308 (post 2014, pre SFP). It's between 260 and 6.5CM. I still have the large fining pin setup in my gun; is there one round that would be more likely to cause me issues with pierced primers than the other?
AI large firing pin and 260 vs. 6.5 CM?
- Thread starter dms416
- Start date
Lots of opinions on this. I say buy the creedmoor and shoot lapua brass. I shoot an AW with a terrible Pin profile on it, but it has no issue with small primer creedmoor brass with hot loads.
I've read that it may have more to do with the firing pin fit in the firing pin hole.
Some say avoid the small primers
Some say avoid high pressures and load on the mild side
Others have zero issues no matter what they do.
I'm thinking there's not much one can do until they try and I'll just pick one and see what happens.
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The one repeated most often around here is simply the large pin with with a small primer being a no-no. The cartridge that started all the drama was the 6.5x47 lapua and it's offspring, which people love to push hard to attain creedmoor and .260 velocities. No mystery that the weak spot of the caryridge gives up first. Even my gun pierced some primers (like 2-3 in the first thousand rounds) early on with that cartridge. I adjusted the pin protrusion and loaded safely, no issues for the next 2000 rounds. The small primer creedmoor has shown no propensity to pierce for me, regardless of
load. I agree about the other factors like pin fit, and pin profile, and pressure as the primary factors. As a long time .260 shooter, I think the new premium brass available for the Creedmoor makes it an obvious choice if youre starting from a clean slate.
I have an AW that will consistently pierce primers with the 260 loads at any kind of useful velocity (above 2750fps). This is a large primer case. Other people never have a problem which is where the debate comes in. I use Bartlein barrels from AI and they will always blow primers. Adjusting the firing pin protrusion didn't help. The rifle just doesn't like running that round without piercing primers.
You will have to try the rifle to see what happens. If you are piercing primers, you will need to get it bushed to a smaller diameter on the bolt face.
You will have to try the rifle to see what happens. If you are piercing primers, you will need to get it bushed to a smaller diameter on the bolt face.
I have an AT with a large firing pin - If you get the bolt bushed, can you still shoot .308 and other large primer cases?
Probably the only question may be in regard to excessively hard, milspec primers. I had an action (not an AI) that was more geared toward competition 6/6.5mm rounds so it wouldn't pierce primers. I ran some factory Black Hills loads through the gun and it did NOT care for the hard, CCI Mil primers that they use. I would say there was a 25-30% failure on the primers. It did other primers/loads just fine. Regarding AI and your AT, I would bet that they made sure they were getting positive ignition on milspec primers, but the "no free lunch" concept and my previous experience remain in the back of my head.
I run an AE mark3 with a regular firing pin and have zero issues with the small primers.
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yeah. I would go with the 6.5 creed for other reasons over the 260. the firing pin wont hold you back with either.
BUT..... I would (and did, as I had the same setup - post 2015 AX308 w/ LFP) send the bolt to Wade at Stuteville Precision and have him bush it and turn the pin down to a small firing pin.
I shoot 6.5x47 so really wanted the SFP, but I think its a great upgrade (about the only thing you really need to "upgrade") on these rifles
BUT..... I would (and did, as I had the same setup - post 2015 AX308 w/ LFP) send the bolt to Wade at Stuteville Precision and have him bush it and turn the pin down to a small firing pin.
I shoot 6.5x47 so really wanted the SFP, but I think its a great upgrade (about the only thing you really need to "upgrade") on these rifles
When I first got my AT I was piercing a few primers in my 6.5 Creed barrel. I adjusted the firing pin protrusion and I have had zero issues since. I've shot 6.5 Creed, 6XC, 243, and of course 308 with no problems. You should be fine with either.
