Looking for those experienced in hipower using the AR 15 platform. Have you found the extra step worthwhile?
I do not crimp. I get very good accuracy and have not had a problem after many thousands. A lot of people do crimp for semi-autos for safety reasons.
Load up 20 crimped and 20 uncrimped and compare results.
I found the uncrimped did better but there wasn’t a big difference.
If you don’t anneal and have brass with mixed firings crimping, might help with more consistent neck tension.
I don’t crimp, my two Rock Rivers shoot 3/4 groups with 62 grain Barnes
No crimp needed. If you want a little more neck tension, chuck the decapping rod in a drill and run the expander ball on a whetstone to remove about.001" off it.
m1rifleman
Its a completely unnecessary step until a bullet moves in the case. In a semi-auto, I crimp everything. Large bore bolt action calibers as well. I do it in an effort to not be sued if something happens. Try this sometime....take a inertia bullet puller...crimp a round, the next not. You will see the difference. Then, try that with a factory round.
Charlie
RCBS makes a taper crimp seating die that has more of a gradual crimp than their standard seating dies. If your brass is all cut to the same length you can adjust to what ever amount of crimp you want. In bolt action rifles it is no visible crimp.
In AR's I like a bit of a crimp. It may not be needed but it gives me a feeling of confidence that things are not going to come apart. Especially for those rounds at the bottom of a long magazine.
kwg
This one v v v
https://www.midwayusa.com/product/1012080214?pid=353847 The RCBS AR Series die set is a must for any progressive reloader. The taper crimp seating die is helpful as it is bit a more forgiving die for crimping cases that have variable case lengths helping to reduce the number of bulges and buckled shoulders when crimping in bullets with a cannelure. Shellholder sold separately.
Use a Lee Factory Crimp Die and adjust the crimp tension to suit yourself. I put a light crimp on every load to hopefully get consistent neck tension. YMMV
I crimp for auto and lever guns. If it is needed not sure the added safety of not setting A bullet back is enough of A reason for me.
Accurate Reloading did at test using a proven 308 loads, overall it improved the accuracy by 10%. A critical aspect of accurate loads is the release force, That's why F-Class shooters have taken to annealing the cases every loading. Makes sense, smokeless powder requires pressure, if the pressures are uneven, so will the burn. I can't be bothered anealling, so I crimp. For range Bang, I have used brass well beyond the recommended number, unnannealed cases don't hold bullets worth a $hit. So I crimp. I use a Lee collet crimper.
A few years ago, I tested 150 grain SST in 308W and the crimped loads had a lower SD and better accuracy.
I had also tested 168 BTHPs but saw no significant difference with/without a crimp. I have been shooting those uncrimped out of a Ruger SFAR with no issues and happy with the accuracy.
This past weekend I was testing 165 gr. Interlocks and the loads with no crimp outperformed the crimped loads. I have improved my case prep recently, and that may play into this.
I am now loading 155 BTHPs with cannelure for the SFAR and those do get a light crimp with the LFC.