Crimp question
- Thread starter Akula69
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Akula69
Member
Measured with a micrometer before crimp.
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OP
Akula69
Member
That is the plan...as soon as I can get some time off!
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OP
Akula69
Member
All right...the time in the loading room yesterday afternoon turned up some interesting results.
First - the cases were measured again with a ball caliper and I found the neck openings to vary between .306.5 and 308. I put the mandrel back into the sizing die and ran 10 cases through. When measured they were dead nuts on .308, so I'm happy with that. Ran all the rest of the cases, randomly measuring some. All passed.
Second - broke down and measured the projectiles. I had purchased a box of 100 from Brownells (yes, I track that stuff...OCD is a bad disease) and two from a local Academy store. The box I was working from was the Brownells box, and put of 100 projectiles, 68 were at or below .307, with some coming in at .3055. I have contacted Brownells with the lot number to see about replacement or refund. In a random measuring of projectiles from the other two boxes I found all to be .308
Third - I loaded up 5 rounds (H335 at 27.8 grains and projectiles from the Academy box) and checked each and every one for bullet setback without using the crimp die. Initial COL was 2.535 (1.210 on comparator) before testing neck tension...no setback under normal pressure, but when loaded into the magazine and cycled through the action I noted 3 of the 5 experienced setback in the range of -.002 up to -.010.
Fourth - I pulled the first 5 projectiles and re-sized the cases. I loaded 5 more (different cases) and gave them a light crimp - just a slight roll into the cannelure. Loading and cycling these produced no measurable setback, so I loaded 25 more and tested them as well - no change.
Conclusion - (1) I somehow ended up with a box of projectiles which either missed QC or were mistakenly shipped anyway. (2) I needed to resize the cases even though they were new.
I 'assumed' new components would be good, and should have checked them randomly before using them. I am glad I learned the lesson (again) this way instead of blowing up my weapon....
Thanks to everyone for the assistance!
First - the cases were measured again with a ball caliper and I found the neck openings to vary between .306.5 and 308. I put the mandrel back into the sizing die and ran 10 cases through. When measured they were dead nuts on .308, so I'm happy with that. Ran all the rest of the cases, randomly measuring some. All passed.
Second - broke down and measured the projectiles. I had purchased a box of 100 from Brownells (yes, I track that stuff...OCD is a bad disease) and two from a local Academy store. The box I was working from was the Brownells box, and put of 100 projectiles, 68 were at or below .307, with some coming in at .3055. I have contacted Brownells with the lot number to see about replacement or refund. In a random measuring of projectiles from the other two boxes I found all to be .308
Third - I loaded up 5 rounds (H335 at 27.8 grains and projectiles from the Academy box) and checked each and every one for bullet setback without using the crimp die. Initial COL was 2.535 (1.210 on comparator) before testing neck tension...no setback under normal pressure, but when loaded into the magazine and cycled through the action I noted 3 of the 5 experienced setback in the range of -.002 up to -.010.
Fourth - I pulled the first 5 projectiles and re-sized the cases. I loaded 5 more (different cases) and gave them a light crimp - just a slight roll into the cannelure. Loading and cycling these produced no measurable setback, so I loaded 25 more and tested them as well - no change.
Conclusion - (1) I somehow ended up with a box of projectiles which either missed QC or were mistakenly shipped anyway. (2) I needed to resize the cases even though they were new.
I 'assumed' new components would be good, and should have checked them randomly before using them. I am glad I learned the lesson (again) this way instead of blowing up my weapon....
Thanks to everyone for the assistance!
Blue68f100
Member
It's not uncommon to find bullets that are under size, the reason for checking. If you contact the mfg of the bullets in most cases they will request a few to check. If they determine their bad they will instruct you how to proceed. Some require them to be sent back, once they receive them normally they will be replaced at a 2 for 1 ratio. So if you end it a box of 100 you get 200 in return for your trouble.
Glad you got everything sorted out.
Glad you got everything sorted out.
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