Small firing pin for 6.5x47 Lapua ???

[Badfinger]

I have an AIAT and I'm looking to have a 6.5X47 Lapua barrel spun up. Is it necessary to use a small firing pin to avoid problems?

 

[buffybuster]

Short Answer: Yes

Depending on the actual FP hole diameter and the fit of the FP you could shoot it as is. But you will likely experience some combination below:

• Primer cratering
• Primer flow into FP hole
• Pierced primers

Even magnum SR primers are thinner than LR primers, with the larger unsupported FP hole, the primer cup is going to flow at lower pressures. To not have those issues you're going to have to back off the loads.

You can have the FP hole bushed at a later date, so I would do some load development and monitor the primer flow situation with your velocities. If you get the velocity you're looking for with acceptable primers, then you're GTG. If not, the bolt needs to be bushed.

 

[Badfinger]

Thanks for the response. I have a new bolt with small firing pin and the original bolt with a large firing pin. But I was considering using the new bolt with the SFP for a .223 conversion and now it sounds like I would still need to replace or bush the bolt with a LFP.