Accuracy International bolts are hard

[carlsbad]

Here are a couple of photos of one I just bushed (different lighting). 2 tone is because the hardened boltface wouldn't take the cold blue. I kindo liked it so I left it.

 

[Dusty Stevens]

Looks like they did a hardness test on it- wonder what it was?

 

[eric32]

@carlsbad

Did the owner have any primer issues?

 

[carlsbad]

Eric,
Yes, primer issues are apparently common with the AI bolts shooting high pressure rounds. Most smiths won't bush them because they are so hard. AI sells a replacement bolt with small pin for $800 is their solution.

--Jery

 

[carlsbad]

Dusty,
The bolts are quite hard, similar to 17-4ph H900 which is in the rockwell C38 to C40 range.

Additionally, it is case hardened and the surface is like ceramic. It would be unworkable if the surface harness were deep.

That hardness test was done prior to case hardening I'm sure.

--Jerry

 

[eric32]

I have heard that but i have run my AI AT with 6XC up to 3100fps with no issues, but i suspect that i was using large primer brass tho, i might just have use some SRP and see if I run into any issues

 

[carlsbad]

Eric,
the firing pins that have been sent to me were all .075" which will generally give you problems with some rounds.

I am shooting 6xc but I never shoot a firing pin over .060" nowadays...however, I will say that I don't see nearly the pressure signs in 6xc as I do in other rounds and that could be your key to success.

I've heard from other AI owners that there is apparently a worldwide waitlist quite long for the small firing pin bolts.

--Jerry

 

[eric32]

Jerry,

Thanks for the info, if i start running into problems i will give you a shout. Keep up the great work.

 

[shoot4fun]

I have heard that but i have run my AI AT with 6XC up to 3100fps with no issues, but i suspect that i was using large primer brass tho, i might just have use some SRP and see if I run into any issues

My understanding is that the AI has a tendency to pierce primers with most 6.5 calibers, large or small. I have owned as many as four AI rifles at the same time, two AW and two AX, and none of them ever pierced a primer. I still own two AW rifles. One is my dedicated 308 and the other currently wears a 7 twist 22-250 barrel. Neither has ever popped a primer. At one time I had a 260 Rem barrel screwed on one of them (AX IIRC) and never had any issue with it.
Yet to shoot any SRP brass in either and I think you're right about the issue surfacing when SRP brass is used in large pin guns.

 

[eric32]

I am going to try to run some SRP just as a experiment but i really don't wanna be the guinea pig for that but i am curious

 

[shoot4fun]

I am going to try to run some SRP just as a experiment but i really don't wanna be the guinea pig for that but i am curious

I've seen pics of a couple of AI bolts, mostly AT rifles, that had pierced primers. The steel may be hard but not hard enough to keep the bolt face from getting pitted from the heat.

 

[eric32]

then hard pass it is