[redyak3]

I put a slight roll crimp on my 9mm reloads and they work fine. A couple of the guys at USPSA shoot last weekend said that I should back off some on the Hornady die seating die to get a more tapered crimp. I'm thinking if it works, leave it. What do you folks think?

 

[jfdavis58]

Roll crimping auto-pistol rounds is ILL ADVISED; they typically headspace on the case mouth.

Taper crimping is something that can be done and if done, done lightly; just enough to hold the bullet in place as it rides up the feed ramp and into the chamber---0.001 to 0.003 less than the nominal case mouth dimension is typical.

 

[agalindo]

Roll crimping auto-pistol rounds is ILL ADVISED; they typically headspace on the case mouth.

Taper crimping is something that can be done and if done, done lightly; just enough to hold the bullet in place as it rides up the feed ramp and into the chamber---0.001 to 0.003 less than the nominal case mouth dimension is typical.

+1

Over crimping can result in excessive pressures.

 

[redyak3]

Thanks for the info:
I backed off the crimp on the die. Does anyone use the Hornady Taper crimp die? My COL is 1.075 w/5.8gr Power Pistol using 115gr MG JHPs. I had good results at last weekend's matches. The reloads shot much better than the S&Bs I've been using.

 

[fredj338]

+1

Over crimping can result in excessive pressures.

Unless the roll crimp is severe & you are using an uberfast powder, like Clays, running max. you'll have a hard time increasing pressures much by crimping. The crimp shown is pretty mild for a roll crimp, if it's working fine for you, leave it alone.

 

[Mercmar]

You should never roll crimp, unless there's a cannelure into which to roll the crimp. Get a taper crimp die for that 9mm!

 

[mongoose33]

I loaded up some 9mm rounds tonite using Delta 115gr FMJ bullets, some were crimped, some not, some using RP brass, some using Win brass. I also used two different powders (Bullseye and Titegroup) as well as two different loads for each powder.

That's 16 combinations (80 rounds, 5 for each combo).

I'm hoping I can get out to the range tomorrow. I have a chrono, so I'll check velocity for each round. It'll be interesting to see what effect a crimp has on performance.

I'll report what I learn here.

 

[zmmnm3]

Try the Lee Factory Crimp die. It resizes and taper crimps the cartridge back to original specifications. I use these for all rimless cartridges and they work great and are very reasonable priced..

 

[mongoose33]

Try the Lee Factory Crimp die. It resizes and taper crimps the cartridge back to original specifications. I use these for all rimless cartridges and they work great and are very reasonable priced..

That's what I used in making up my test rounds. I'm hoping I can get off in time this pm to do the tests.

 

[mhillsing23]

Let us know how those tests go. I use Titegroup for my 9mm loads as well. It will be interesting to see the velocities you get.

 

[redyak3]

Since I have the Hornady setup, I have the Taper crimp on order from Midway. I'm happy with the LNL. I haven't chronoed the adjusted crimp loads yet but I was getting an avg of 1210 fps with the first batch using Power Pistol @ 5.8 gr. I hope I'm not making a mistake by messing with a setup that works, as I went through about 200 rnds at our last IDPA and USPSA matches without a glitch.