Taper Crimp vs Factory Crimp

[markm]

I've done crimp tests before, but never a head to head Taper vs Factory crimp specifically for accuracy. I also left 5 rounds uncrimped to see if they still shoot much worse (like they did last time I tried this)

I set up the taper crimp on my single stage and I'm not sure if have it set deep enough. The round on the left also looks asymmetrically crimped for whatever reason:



Guys have asked here in the past where I set my FCD, and I finally got a pic. I turned the die down a few thowie because I think wear on the die was giving me less crimp than before.



We'll shoot these this weekend, and post results. My worry is that due to the hefty chamfer the Giraud trimmer leaves, the taper crimp might be too light. But I also don't want to go too aggressive. If the taper shoots the same as the NON-crimped, I'll redo the test with more taper.

[HKGuns]

Interested in your results. I think you are a bit more agressive than I am with the FCD. But I'd have to look at pictures like you posted of my rounds to be sure.

[markm]

Interested in your results. I think you are a bit more agressive than I am with the FCD. But I'd have to look at pictures like you posted of my rounds to be sure.

Compared to some of the crimps I've seen on some factory m193 style ammo, this crimp is pretty light. I'm liking the looks of is after turning the die down a little.

[BobinNC]

Mark,

Are all those un-cannelured bullets?? RMR's perchance??

[markm]

Mark,

Are all those un-cannelured bullets?? RMR's perchance??

Yep. 69 gr RMRs. I still have the 75s loaded for separate 1k shooting, but I wanted to do this test on a known bullet... so the 69s are it.

[triggerjerk]

Markm, you must've read my mind. Look forward to your results. I imagine you've already imagined that uneven neck thickness, some lack of case support within die, or unsquare case mouths may contribute to uneven taper crimps. I was hoping you'd do this test because I typically have 1 to 2 thou headspace difference. My unannealed or not same lot cases may have 4 or even 5 thou headspace diff. If I don't adequately lube cases (to minimize lube build up/hydraulic denting on shoulders during sizing), I end up with shorter headspace on those cases. My Kwik trim inxedes off of shoulder and contributes to case oal variance. With your Giraud trimmer indexing off shoulders, I was gonna wonder about taper crimp consistency in light of headspace variance and shoulder trim indexing contributing to oal variance which may adversely affect said taper crimp consistency. So much for overthinking it!!! I eagerly await the reality of results from you actually shooting!

[MegademiC]

Can you measure the crimp? I'll post a pic and measurement of mine when I get home... also using rmr 69s.

Cant wait for results.

[markm]

Markm, you must've read my mind. Look forward to your results. I imagine you've already imagined that uneven neck thickness, some lack of case support within die, or unsquare case mouths may contribute to uneven taper crimps.

Definitely. I crimped these (taper) on my single stage for the test. That shell holder sometimes gets debris. I try to watch that every case inserts completely for sizing, neck expand, etc. But junk gets in there.

The RCBS mandrel would mean taking the die apart. If I get time, I'll do it. I'd like to see if there's visible wear anyway. I've sure ran well over 50k pieces through it by now.

[545Warman]

I use the taper crimp for pistol/straight walled rounds & factory crimp for rifle/necked down rounds.

[markm]

I'd love to find that the taper could be as accurate as the FCD because I simply wear dies out. My competition bullet seating die is dead and my FCD die is long in the tooth. (Neither of which are in stock now to replace) I'd love to have a setup with no moving parts to wear out.