Crimping

[JJD]

How many of you reloaders crimp your center fire cartridges?
Just wondered how it effected performance and pressure?

I am running some pretty hot loads through my 300 win mag. Although I have noted no bullet movement as a result of recoil thus far,  I figure it can happen.

[haulinbass]

I don't crimp nor does my buddy. I shoot a 270wsm and he shoots a 300wsm and we have had no problems and my buddy is a reloading encyclopedia himself.

[2labs]

I wouldn't crimp. Be worried about excessive pressure. Put one of your rounds in a bullet puller and you'll see they don't move that easy.

[iusmc2002]

I crimp all my center fire rounds.  Some may only have a light crimp, but all get crimped.  I like to know that all the rounds are being driven from the case with consistent pressure because there are fluctuations in brass, and neck tension.  I notice the difference between crimped/us crimped accuracy in my 300 WM. It isn't great, but is is noticeable to me

[grundy53]

I don't crimp except for my tube fed rifle.

[carpsniperg2]

Depends on what I am loading for. If it's a tube fed rifle I think it's best to give them at least a small crimp. On some of my larger semi auto rifles I have run crimps but don't think I really needed to.

[BULLBLASTER]

The only thing I crimp is my 375 h&h

[Jason]

I always give my 300wm a tight crimp because of the short neck, and I put a light crimp on all my other large rifle center fire cartridges.

[JJD]

I get the tube magazine issue, makes perfect sense.

Next time I can get out;
I will load a magazine full of cartridges that have not been crimped, fire 1, pull the rest and measure the bullet seated depth with a comparator.
I will repeat the process till all rounds are fired, Last round will have been subject to 3 previous rounds fired above it.
This should be a positive test for movement.
Will also measure/look for signs of increased case pressure and change in point of bullet impact and group size.

note;
I use a Lee Collet sizing die that I have taken .001 off of the collet in order to maintain a slightly tighter fit.

I understand that just because a bullet does or doesn't move in my reloads does not mean it will be the same for everyone's loads.
Just food for thought.

 

[Blacklab]

All my center fires got a hug for years. Now not so much and I really haven't noticed much of a difference  (gas guns)

[Spawnstar]

The only calibers I crimp is auto loaders lever guns and revolvers.

[magnumb]

The only calibers I crimp is auto loaders lever guns and revolvers.

 .............I don't even consider crimping my 300 RUM and there's a bit of recoil/pressures goin' on with that rather warm load.  After 3 rounds, measurements of AOL on the 4th cartridge have shown no appreciable difference in length.

[HawkCreek]

I've begun crimping tests with a .308 no I don't think it's needed (I haven't found any bullet creep without crimping). But in the rather limited testing so far there HAS been an increase in accuracy. I'll need several more range sessions to confirm this but it's been a fun thing to play around with.

As an interesting aside a light crimp moved my POI about 3/4" (maybe a little less) at 100 yards.

[dawei]

I crimp cartridges for my lever guns...
7/30 Waters
30/30 Winchester®
444 Marlin®

I do not crimp for my...
7mm Remington® Magnum
30/06 Springfield®

[JJD]

Above experiment completed and I did not experience any bullet movement at all.

Next going to experiment with consistancy with the Lee Factory crimp die.
Can't imagine it will be any better, but ya never know till ya give it a shot.  Yeah, it was intended