Newb Question: Whats the Deal with the AI small firing pin?

[sasquatch98226]

So I am thinking of going to play with the Big Boys in the AI club. I am thinking of getting a post 2014 AT so I can get the quick change barrel. Looking at purchasing a 6.5 Creed rifle, and a 6.5x47 second barrel. That way if I am in a pinch I can use Prime ammo, or if I want to load, I can go 6.5x47.

With that said, I read there are large and small firing pins in AI's, and as I understand, the large once pierce primers? Since the 6.5x47 is a small primer, and the creed is a large primer, will that make a difference?

Thanks.

 

[mercracing]

I know new AX’s were shipping with the small firing pin, but I haven’t heard anything about the AT’s. I’m sure someone will chime in here. If you need to know now, I would call Mile High Shooting.

 

[Kiba]

Depends on the caliber and how hard you push it.

You shouldn't have primer issues with 6.5 Creedmoor with large primer brass; I never did with my AE with the large firing pin even when handloading to the warm side of things. However, years back there were several people having primer issues with .260 and 6.5 Creedmoor with the large firing pins. Some were able to solve the issues by reducing the firing pin protrusion, others had to bush the bolts and turn the firing pins down.

6.5x47, being a small primer round, would be more likely to have primer issues with the large firing pin especially if you reload and start pushing towards the high end of the charge range. Same with other small primer/high pressure rounds like 6 Dasher.

The small firing pin will be the most versatile when it comes to avoiding primer issues regardless of caliber or small/large primer.

Any 2015-up AT or AX308 should have the small firing pin bolt as standard. For 2014 and earlier models, you can either have the bolt bushed and the firing pin turned down, or buy a new small firing pin bolt and firing pin from AI. If you’re looking at a used rifle, anything with a 15 and up as the first 2 digits of the serial number should be good to go.

One telltale is seeing the long flutes on the bolt body in the ejection port when the bolt is closed; the large firing pin bolt bodies don’t have those flutes and the bolt body showing in the ejection port will look smooth. Obviously, a picture of the bolt face is the best way to verify.

 

[Hairy Biker]

You cannot bush the old bolts. Too hard.

 

[Kiba]

You cannot bush the old bolts. Too hard.

Yes, you can. Wade Stuteville bushed my AE bolt and a friend's AW bolt. Dave Tooley used to bush them as well; he stopped for a while when he was doing the barrels for AINA as AI thought it was a bit of a "conflict of interest"-- not sure if he's doing them again. Dave is the one that referred me to Wade for the bushing job during that period he wasn't doing them at the request of AINA. And now Chad and the gang at LRI can do them.

The nitride treatment AI uses may present a hard surface layer, but with proper tooling it's not an impossible job.