Gunsmithing 6.5x47 Firing pin problem

[Mr.Kirk]

I recently wrapped up a new 6.5x47 Lapua using a surgeon action. I purchased the s/a repeater ideal for a basic 308 build and already having the correct bolt face. I constantly had hot loads while developing a round for this rifle, even when using known light loads from another rifle. I was dimpling and busting primers. I finally damaged the sear on my trigger while killing a primer on a test load (that I really like.)
While the trigger is off to be repaired we looked at the firing pin and realized that it is long for the large rifle primer used in a 308 and should be shorter for the small rifle primer used in the 6.5x47.
I am hoping that this is the main reason for my primer problems.

I wanted to share this oversight with all of the other amateur gunsmiths out there.
That last primer I blew was the 17th round of the 3rd relay.

 

[DarinR]

Re: 6.5x47 Firing pin problem

Zak Smith writes about this issue in his articles on the 6.5x47 Lapua in the Arctic Warfare.

I understand the firing pin is modified and firing pin hole in the bolt face is sleeved.

I am having a barrel in 6.5x47L made up now by GAP for my AW and I expect to have to do something after shooting a few rounds through it and seeing what happens.

Darin Reiss
FFL/SOT in Haysville, KS

 

[distantfoe]

Re: 6.5x47 Firing pin problem

I know several rifles that had their firing pins bushed by Gre-tan. It fixed the problem. The firing pin is just too big.

 

[Mr.Kirk]

Re: 6.5x47 Firing pin problem

Just finished the work on the bolt and installed a remington trigger for while my fancy one is off to surgery.
I am going to shoot leftovers from my tests tomorrow or Sunday and see where I stand.

 

[Wild_Bill]

Re: 6.5x47 Firing pin problem

Ok you need to have the bolt bushed and the firing pin turned down to 62 thou.

Also the bigest thing if you are using hot loads use only Rem 7 1/2 primers they have thicker cups and do not blow as easy as other primers.

We build heaps of 6mm BR's, 6X47 Lapuas and even 223's with 80 and 90gr projectiles the bigest thing is using rem 7 1/2 primers and have that bolt bushed you will have no more problems.

Also the Rem primer burns hotter for longer so it is closer in burn rate to a large rifle primer than any other small primer so it tends to give the best performance in the larger cases with large charges of slow powder for the small primers.

 

[matchking]

Re: 6.5x47 Firing pin problem

It is a common problem, though the majority of people will not experience it. AIs seem to suffer the most and, like stated, swapping primers can solve the problem.

 

[RBros]

Re: 6.5x47 Firing pin problem

Bushing the firing pin will solve your problems....We do it do every rifle we build on Rem 700's and customs with large pins, especially for the small rifle primer cases. Gre-Tan will take good care of you and is fast.

 

[steve123]

Re: 6.5x47 Firing pin problem

Bill,

What do you think of the cci450's magnum compared to the rem 7 1/2 primers?Do they flow about the same with warm loads?

Steve

 

[Glen Seekins]

Re: 6.5x47 Firing pin problem

You can run much hotter loads if you bush the firing pin to a smaller size. the large firing pin has a large hole in it and doesn't support the primer very much (surface area contact) so they pierce easy(er).

Swapping primers will help just as much as going DOWN in your powder charge. CCI's have a harder cup, but we still pierced them too.

 

[110len]

Re: 6.5x47 Firing pin problem

Charlie Robertson at Score High Gunsmithing will bush the firing pin hole and turn down the firing pin as well. Great service.

 

[260shtr]

Re: 6.5x47 Firing pin problem

I switched to Wolf Small Rifle Mag primers and the primer cratering is much less. Probably still have it bushed.

 

[Mr.Kirk]

Re: 6.5x47 Firing pin problem

Did the work on the firing pin and tested leftover rounds from test loads on Sunday. Turns out only one load was really hot, the one that broke the trigger. The dimpling on the others is non existent now.
Now just waiting on my big box of group buy brass.

 

[dmgreene]

Re: 6.5x47 Firing pin problem

What work did you do? Did you turn the firing pin down and bush or just bush the bolt?

David

 

[Criver600]

Re: 6.5x47 Firing pin problem

Greg Tannel has installed bushings and reduced the firing pin diameter in three of my AI's and cured the blanking problem with small rifle primers

 

[Mr.Kirk]

Re: 6.5x47 Firing pin problem

Gave it to my friend who is a gunsmith this time.
I think that he did both.

 

[Casey Simpson]

Re: 6.5x47 Firing pin problem

I solved that problem in mine by using CCI #41 primers made for M16s to prevent slam fires.