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Crimping Rifle Rounds

10K views 40 replies 12 participants last post by  rtockstein 
#1 ·
#9 · (Edited)
Yeah, SS put that up in another thread on crimping rifle bullets a little while ago. see: http://utahwildlife.net/forum/18-firearms-reloading/167370-crimping-rifle-bullets.html

As stated in that thread I've duplicated some bolt action reloads that I have some good chrono data, but added a crimp with a Lee factory crimp die this time. My eyesight is giving me fits so comparing "before and after crimp" targets is not valid, but I can compare chrono readings. (And I was shooting with my eyes closed back then. Now I'm shooting with my eyes open.) I'm going to do 250 Savage, 308, and 25-06 in that order. Just haven't taken the time to do so.

There's not much spread in chronograph readings on factory ammo, crimped factory ammo of course. Most all non-monolithic factory ammo is crimped by the way. I have a hard time getting my non-crimped load chrono readings as consistent as the factory crimped rounds. And yes I'm doing all the reloading things down to 6 decimal points, so please don't go there. So I'm crimping some bolt action reloads to see if I can narrow the fps spread.

I grew up in the part of the country, and at a time, where pump and semi-autos rifles were the norm. All factory ammo was crimped and those that reloaded crimped everything. Course we were a bunch a hillbillies; ate liver, whole birds, roots n berries.

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#11 ·
Is crimping bad? see: http://utahwildlife.net/forum/18-firearms-reloading/167370-cri

Let me warn ya, guys are gonna get on here and....uh....waitaminute, what crimping thread am I on? Mine or Bax*s? oh....Bax*'s, OK.

Let me tell ya, guys are gonna come on here and say that crimping is going to ruin yer brass. Well they're right, you'll prolly only get 6 loadings out of it instead of 12. That's with a roll crimp though. :smile:

I have to admit factory crimps are segmented and don't "iron out" so well when resizing. That's OK on factory ammo cause it usually needs to be trimmed after the first firing anyway, but not so OK when using a Lee factory crimp die on brass that's already been trimmed.

ooh, top of the page!

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#17 ·
Let me tell ya, guys are gonna come on here and say that crimping is going to ruin yer brass. Well they're right, you'll prolly only get 6 loadings out of it instead of 12. That's with a roll crimp though. :smile:

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6 Loadings !? I'm lucky to get 4 shots before my cases start to show signs of case-head separation. In fact, I mark all my cases now with a number so I know to throw them in the garbage brass bucket after the 4th shot.

This has been a factor in my .270's more than my 7mm but I don't like to take chances. I neck size the 270 brass now after the first firing but still don't go past 4 shots.

I crimp my pistol and .223/5.56 loads but none of the others. I don't like the though of roll crimping my rifle rounds, but may look into a taper crimp or factory crimp die for those in the future.
 
#19 · (Edited)
closet crimpers are coming out



A closet crimper? :smile:

I was kinda being sarcastic about getting the 12 re-loadings. That's tough to do if you full length size and I'm assuming most of those here FL size. I neck size a lot and normally get more loadings out of my brass than if full length sizing.

Roll crimping can be a pain. I do a lot of revolvers so I'm use to it. A collet-type crimp, like made with the Lee Factory Crimp Die, is easy, more goof-proof, but it's tough on the last 0.005" to 0.010" of the cartridge mouth.

Interesting that you bring up the 270. I'll never use all the 30-yr old un-crimped 130 gr Core-Lokts 270 reloads I have, good grief. They're all FL sized, not any longer than the recommended COL. They cycle well whether in my bolt action or pump. FL sized 270s can be a little "stretchy" so later I went to neck sizing, and for bolt actions went to moving the bullet out closer to the hole some. But pump rifles can be troublesome to stroke sometimes so cartridges for pumps work best if they're FL sized and not too much longer than the recommended max length.

Using flat base projectiles like the old Rem Core-Lokts, Partitions, or others popular back in my "era", puts a lot of the bullet in the long-necked 270 brass. There's plenty of neck tension there so I don't crimp pointy 270 bullets like for most other pump rifles.

I do crimp the 270 round nose bullets though; force of habit I guess. A round nose bullet doesn't go up the ramp on a pump as freely as a pointy bullet does. If you're excited and jam a cartridge a lot of bad things can happen to an un-crimped bullet when you're trying to dislodge it from the receiver....uh...don't ask me how I know that.

I'll shut up, prolly not many on the UWN using round nose bullets in their 270. :smile:

I'm putting some feelers out for my next reloading thread; neck sizing vs full length sizing. It's gonna be a goodun', I can feel it. I'm talking 30 pages, 45 pages if Bax* duplicates my thread.

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#26 ·
this is my favorite thread



Ah, ha, ha, ho, ho, hee, hee

When I first moved out West I used round nose bullets in my 270. Made sense to me since I had a coffee can of them. One of them Wyoming cowboy dudes I was working with took one look at my ammo and said "150 grain round nose bullets kinda defeats the purpose of a 270 doesn't it?" WTF? Geeze, glad I wasn't using my 12 gauge shotgun and slugs. :smile:

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#29 · (Edited)
I have a mixed relationship with crimping rifle rounds. When I first started reloading I decided to load a few boxes of 30-06 combined technology ballistic silvertips. I thought it would be cool to crimp them because my reloading manual talked about it. Well, I slightly over crimped (roll) about 150 rounds, slightly misshaped my brass. I couldn't tell until I tried to chamber a round and the bolt wouldn't turn over. That led me down the road of various bullet pulling devices. Man, thinking back I have made many many mistakes reloading...getting brass stuck in dies, using the wrong primer for the round, deforming brass/bullets and many other stupid mistakes, and I have yet to blow myself up--so lucky. Oh the fun!

Since ruining a bunch of rounds crimping rifle bullets I now follow the rule that I don't crimp unless the bullet has a cannelure. I only roll crimp as I am a revolver guy, but after the AR blew up thread maybe I need to buy a taper crimp die for my 223 rounds.

I would only have several thousand to run through it--sounds like an enjoyable day! :shock:

Being that most all of my 223 ammo is Hornady vmax without cannelure would it be a prudent investment of time and $ to get one of these?

https://www.midwayusa.com/product/353847/rcbs-ar-series-taper-crimp-seater-die-223-remington

I have never had an issue with ARs moving bullets in my reloads but neither did Al until his blew up.

Anyone every try to roll crimp plated lead handgun bullets without a cannelure--that's some fun! On a whim, I bought a bunch of plated rounds for my 44 mag and regardless of my aggressive roll crimping they still work themselves out even with 44 special power loadings. Stupid bullets, I can only load three at a time, otherwise they work themselves out and jam my cylinder. Sorry for the derailment, this thread is about rifles.

So is it worth buying taper crimp dies for your rifles to use when no cannelure is present or maybe you want to take the bullet out to the lands and can't use the cannelure (bullets look dumb this way)? or just roll crimp super lightly--I don't want to try that again to tell ya the truth.
 
#30 ·
Anyone every try to roll crimp plated lead handgun bullets without a cannelure--that's some fun! On a whim, I bought a bunch of plated rounds for my 44 mag and regardless of my aggressive roll crimping they still work themselves out even with 44 special power loadings. Stupid bullets, I can only load three at a time, otherwise they work themselves out and jam my cylinder. Sorry for the derailment, this thread is about rifles.
I reload alot of plated bullets w/o cannelure... specifically 380 and 40SW Berrys Bullets. I've yet to have a feed issue, but havent really mic'd any to see if they are moving. I doubt the 380 would, but its definitely a possibility with the snappy 40S&W.

So is it worth buying taper crimp dies for your rifles to use when no cannelure is present or maybe you want to take the bullet out to the lands and can't use the cannelure (bullets look dumb this way)? or just roll crimp super lightly--I don't want to try that again to tell ya the truth.
You can crimp most any bottle case with the seating die if you screw it down tighter. I like a slight pressure on my case mouths, but I wouldnt call it a "crimp" per day. IDK if you can even get a dedicated taper crimp for most rifle calibers... never really thought about it, or noticed them being for sale.

-DallanC
 
#32 ·
I did a little test today with identical loads, 5 shots without any crimp and 5 with a crimp using the Lee Factory Crimp Die. Bullets were 110gr Barnes TTSX from a .270

My disclaimer is that this was not my personal best as far as shooting days goes, but still...the crimped loads did not group quite as well. In fact, they shot quite poorly.
 

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#36 · (Edited)
Actually I don't crimp all my rifle reloads. I own a number of pump rifles a few semi-autos. Those get crimped. I've crimped an amount ammo for my bolt actions

Number of firings? That's dependent upon so many variables: caliber, type of powder, powder charge, distance off the lands...more...then there's the brass. The hardness value of factory brass varies considerably from one casing manufacturer to another.

Crimping brass for bolt-actions has been more of an experiment than a habit. I just haven't found the time to test and record all the calibers and loads I've crimped.

One thing is certain; open any box of factory ammo and you'll find most are crimped.


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#37 ·
I believe that most if not all factory round are going to have a crimp on them just for the simple reason that the factory has no idea of what that round is going to be shot out of.

For my bolt rifles I have never crimped while reloading. This runs from a 22-250 all the way up to a .340 Weatherby. On the Weatherby I actually ran a test to see if the bullets were jumping out of the neck by loading the magazine up with the three rounds and then just shooting two rounds leaving the third round in the magazine as I topped it off for a number of times. When I measured the overall length of that one round it was still right where I had seated the bullet.

Now I do have a few rounds that I do place a slight crimp on them and some that get a little bit heaver crimp, it just all depends.
 
#38 ·
Crimping is used to maintain uniformity in rounds. It is not an accuracy thing. If a round is going to be deformed( bullet pushed in or pulled out) from handling, shipping or even just carrying around in your pocket, or from recoil or magazine pressure(spring loaded tubular magazines), then crimping is necessary.

As with any step in the reloading process, accuracy is dependent upon consistency. Ultimately, crimping rounds will help to maintain consistency, overall length, from round to round.

I always crimp rounds that are intended to be used in my lever guns but never crimp for rifles with box type magazines. High capacity box magazines can deform the rounds slightly from recoil the longer it remains in the magazine as you shoot. But that is pretty minimal.
 
#39 ·
From reading through this long thread, I thought you were crimping everything, Goob.

BP, I'm sure the purpose is probably for making the cartridge more robust and resistant to the bullet getting pushed back. But, crimping CAN increase accuracy, not that it always does though. It can help create more consistent start pressures and reduce velocity spreads, due to more consistent bullet hold by the case.

I just need to get a Chrono so I can test all these questions I need answers to!
 
#41 ·
Just as a FYI some of my most accurate round and consistent velocity out of my 22-250 the bullet can be pulled out with my fingers.

No crimp and barely seated
Pull it out with your fingers?! That's madness. I know I could get plenty accurate loads doing that also, but I like the security the crimp gives me and I feel like I get some benefits from it with my particular process. Even if I actually don't gain anything, I like the peace of mind i get from it.
 
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