gyr Posted October 19, 2019 Report Share Posted October 19, 2019 Hello I wonder if someone has experience with using small primers with an Ai AT action? Need to buy some brass and leaning towards small primer Lapua, but want to make sure the AT firing pin will work well? Thanks Quote Link to comment Share on other sites More sharing options...
Ronin Posted October 19, 2019 Report Share Posted October 19, 2019 Measure the diameter of the firing pin first if large diameter is approach with caution Some bolts / fire control are ok some are not and it seems a lottery wether one over the other works or not This applies to all small Rp brass / bolt heads with large fp Quote Link to comment Share on other sites More sharing options...
gyr Posted October 19, 2019 Author Report Share Posted October 19, 2019 Will do. thanks Quote Link to comment Share on other sites More sharing options...
Scotch_egg Posted October 19, 2019 Report Share Posted October 19, 2019 I have first hand experience of this issue. My AT is an earlier model. I believe if your bolt has the fluting showing when the bolt is closed in the action it is of the newer small FP models. easy way without measuring your firing pin is compare with this photo. Large on the left and small on the right. Both From AT’s Quote Link to comment Share on other sites More sharing options...
gyr Posted October 19, 2019 Author Report Share Posted October 19, 2019 Looks like the small one Quote Link to comment Share on other sites More sharing options...
gyr Posted October 19, 2019 Author Report Share Posted October 19, 2019 Pin diameter is 1,59 mm Quote Link to comment Share on other sites More sharing options...
Scotch_egg Posted October 19, 2019 Report Share Posted October 19, 2019 Safe to say that’s a small firing pin. Quote Link to comment Share on other sites More sharing options...
baldie Posted October 19, 2019 Report Share Posted October 19, 2019 Post 2017 [ i think ] all are fitted with the small pin. [ AX and AT , not the AXMC, though it is available as a factory option ] The only cartridge it seems to give issues with is the 6.5 x 47. I've run both large and small creedmoor on my old AX [large pin ] with no issues. I've just come back from testing my other AX [large pin ] with a new .260 ackley improved barrel. Working up carefully, i've just managed to hit 3054 fps with a 142 grain bullet, and no pierced primers up to that. This was on Peterson SRP .260 brass, fire formed. Quote Link to comment Share on other sites More sharing options...
geek Posted October 19, 2019 Report Share Posted October 19, 2019 44 minutes ago, baldie said: Post 2017 [ i think ] all are fitted with the small pin. [ AX and AT , not the AXMC, though it is available as a factory option ] The only cartridge it seems to give issues with is the 6.5 x 47. I've run both large and small creedmoor on my old AX [large pin ] with no issues. I've just come back from testing my other AX [large pin ] with a new .260 ackley improved barrel. Working up carefully, i've just managed to hit 3054 fps with a 142 grain bullet, and no pierced primers up to that. This was on Peterson SRP .260 brass, fire formed. I would value your opinion. I have a 2014 AI AT and I am about to rebarrel in 6.5Creedmoor. I have purchased 200 Laupa small primer cases, do you think this could be an issue? If so, I will just use this brass in the Ruger PR. Thank you and any advice is much appreciated. Quote Link to comment Share on other sites More sharing options...
Ronin Posted October 19, 2019 Report Share Posted October 19, 2019 Bang on the money there Dave 👍🏻 Quote Link to comment Share on other sites More sharing options...
gyr Posted October 19, 2019 Author Report Share Posted October 19, 2019 Firing pin is clear then. Next... small primers with slow powders for the 6,5 creed moor. Will post later, 😀 Quote Link to comment Share on other sites More sharing options...
Dellboy Posted October 19, 2019 Report Share Posted October 19, 2019 3 hours ago, baldie said: I've just come back from testing my other AX [large pin ] with a new .260 ackley improved barrel. Working up carefully, i've just managed to hit 3054 fps with a 142 grain bullet, and no pierced primers up to that. This was on Peterson SRP .260 brass, fire formed. is this the 1200 yard plus answer Dave Quote Link to comment Share on other sites More sharing options...
baldie Posted October 20, 2019 Report Share Posted October 20, 2019 9 hours ago, Dellboy said: is this the 1200 yard plus answer Dave Hopefully Quote Link to comment Share on other sites More sharing options...
baldie Posted October 20, 2019 Report Share Posted October 20, 2019 12 hours ago, geek said: I would value your opinion. I have a 2014 AI AT and I am about to rebarrel in 6.5Creedmoor. I have purchased 200 Laupa small primer cases, do you think this could be an issue? If so, I will just use this brass in the Ruger PR. Thank you and any advice is much appreciated. If you are bringing the rifle in to me, for the re barrel, i'll give you all the info you need on these issues. Quote Link to comment Share on other sites More sharing options...
Scotch_egg Posted October 20, 2019 Report Share Posted October 20, 2019 I will add that it is also primer dependant. My 2014 AT large FP 6.5X47 is fine with CCI BR4’s. It pops CCI 400’s.though. Quote Link to comment Share on other sites More sharing options...
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