Crimping...?

DSS

DSS

New member
Hello, all.

I have some more new guy questions as I begin the process of loading for the first time. I now have a Lee single stage press, and I went ahead and purchased the collet die set, which comes with a full length sizer as well.

First Question: I am wondering how many of you crimp your ammo, and if so, has anyone used the Lee Factory Crimp die? I'd like to load the most accurate (not fastest) loads possible, but they will indeed leave the cozy confines for the wide open spaces when I go hunting. I guess I'm looking for advice on crimping, and if I do crimp, I'll likely use the Lee Factory crimper.

Second question: From where does one derive the "trim to length" of a case? Perhaps I need to buy another loading manual (have the Lee book), but it only diagrams maximums.

Third and final question: If I am loading 52 gr HPBT match (Hornady) and 55 gr HPBT (Berger) in my .22-250 on Reloader 15 powder, and I choose to start at a load of 34gr (roughly 10% below Alliant's published spec), what in what increment should I increase to "work up" to find my best accuracy?

Thanks again to all of the fantastic resources on this forum. You gents are indeed a credit to your pastime.

Drew
 
I did fail to mention, if it influences your input, that I have some saved-up once-fired brass, but also purchased some new Winchester brass, which I plan to load first.

My concoction will be: Win brass, Win WLR primers, Reloader 15, and Berger 55gr HPBT.
 
I've experimented a bit with crimping (with the Lee FC dies) & found that it didn't help with my loads.

Some rounds you just have to, ammo for a tubular magazine like 30-30 or 444 Marlin, for example. Those I crimp.

30-06, 223, 22-250 & such? I don't bother.

The Lee die is cheap, so if you want to play with one the real costs are components & time. Just be sure to have a baseline. Have a known accurate load for a rifle, then back off the charge & using the crimp die work back up & shoot groups to see how they compare. If you find a point where it groups better, nail it down & use it.
 
I don't crimp shells, neck tension has more influence on performance than crimping does. I use 1% as a rule of thumb for increments, as in your case of 34 grains I would use .3 grain increases.
 
Quote:From where does one derive the "trim to length" of a case?

It's listed in reloading manuals, or you can find it on-line.

For the 22-.250 it's listed as Maximum Case Length - 1.912"
Trimmed Case Length - 1.902"
I'm thinking every one I own defines the trim length as .010" shorter than max. (I may be wrong here, but .223, .308, 30-30 all are).

I don't crimp except for tube-fed rifles using a cannalured bullet. I never saw any advantage when I tried it, and backed my seating die off about 25 years ago. If the bullets move, it's a problem with the sizer plug, and you can't "cure" that with a crimp.
 
Nice to know, guys. I'll welcome more advice. So, if every empty I pulled from the first firing in my Savage measures a case length of 1.906, is that a pretty good indicator that this is the "absolute" length of my chamber?

I guess my primary concern with crimping was two-fold: Will the bullet stay in place as I transport it and jostle it a bit (or feed it from the magazine); and will I be needing to seat the bullet to the rifling without the crimp? (I've read also a good "starting point" is .010" aft of seating...)
 
The lee crimper is an exceptional tool. nothing cheap about it. Crimping is more important with high recoiling rifles, tube fed rifles. But if you buy bulk bullets a lot of them have crimp grooves. If i'm loading hunting ammo in my 300 win mag i crimp, 223 for the mini 14 gets crimped, Bullets with crimp groove gets crimped. Compressed loads get crimped. pistol rounds all get crimped. Target ammo is not crimped and ammo with expensive brass/hard to find brass is not crimped unless in a heavy recoiling rifle or tube fed magazine. Factory ammo is crimped to make it safer more consistant ammo. A single shot rifle has no magazine so i would only crimp compressed loads. Crimping shortens case life but it can increase accuracy in some loads. I have had OAL increase on compressed loads and OAL shrink on recoil in magazines. neck tension will not always hold OAL stable. You must decide to crimp or not to crimp on every load you do. Most reloaders do not crimp, but most do not know when a crimp is required for safe reliable ammo under hunting conditions. Crimping if done must be part of load development from the begining.
 
I have experimented with the Lee factory crimp and can tell you it is the best crimper that I have used. I was hoping for more consistency in my loads. Didn't help much. I don't use it because the shortened case life outweighs any benefits I could barely measure from using it.
 
this is a partial list of trim length. rcbs has a page that shows quite a lot more, but im having trouble finding it.


http://www.riflesintheuk.com/trimtolength.htm

Case trimming

Every time a rifle cartridge is fired, the case neck stretches very slightly. Eventually this can lead to chambering problems (and consistency problems if the cases stretch at different rates). After every few firings, it is a good idea to measure the length of your fired cases and trim them to the 'trim to length' shown here if they need it. The picture shows an RCBS case trimmer, available for about £80 at any good gun shop.
RCBS case trimmer
Trim to length data

The following data is taken directly from the The Vihtavuori Reloading Guide for Centerfire Cartridges: Edition 6, 2008.



6mm PPC 1.508"
6mm BR Norma 1.551"
6.5 Grendel 1.516"
6.5x47 Lapua 1.843"
6.5x55 Swedish Mauser 2.157"
6.5-284 Norma 2.161"
7mm-08 Remington 2.028"
7mm-08 Remington 2.028"
7x57 2.236"
7x57R 2.236"
7x64 2.512"
7mm Remington Magnum 2.492"
7mm Weatherby Magnum 2.539"
7.62x53R 2.098"
7.5x55 Swiss 2.181"
7.62x39 1.516"
8x57 JS 2.236"
8x57 JRS 2.236"
9.3x62 2.433"
9.3x66 Sako 2.591"
9.3x74R 2.933"


Imperial Cartridges Trim to length
.22 Hornet 1.394"
.222 Remington 1.693"
.223 Remington 1.752"
.22 PPC 1.508"
.22-250 Remington 1.902"
.243 Winchester 2.039"
.240 Weatherby Magnum 2.488"
.25-06 Remington 2.484"
.260 Remington 2.028"
.270 WSM 2.091"
.270 Winchester 2.531"
.270 Weatherby Magnum 2.539"
.30 Carbine 1.283"
.30-30 Winchester 2.031"
1.862"
2.008"
.30-06 Springfield 2.484"
.300 H&H Magnum 2.842"
.300 WSM 2.021"
.300 Winchester Magnum 2.610"
.300 Weatherby Magnum 2.815"
.300 Lapua Magnum 2.713"
.300 RUM 2.839"
.303 British 2.213"

.338 Winchester Magnum 2.492"
.338 Lapua Magnum 2.714"
.375 H&H Magnum 2.842"
.444 Marlin 2.216"
 
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Originally Posted By: DSSNice to know, guys. I'll welcome more advice.

1) So, if every empty I pulled from the first firing in my Savage measures a case length of 1.906, is that a pretty good indicator that this is the "absolute" length of my chamber?

2) I guess my primary concern with crimping was two-fold: Will the bullet stay in place as I transport it and jostle it a bit (or feed it from the magazine); and will I be needing to seat the bullet to the rifling without the crimp? (I've read also a good "starting point" is .010" aft of seating...)

1) The only thing that has anything to do with "chamber length" is.....chamber length. Case length is unrelated. Chamber length will be anywhere from .025-.035", maybe even .040", longer than a new case. And if brass is shortened even more to "trim to" length, there'll be even more space between the casemouth and the end of the chamber. That's why the case trim thing that people go through with new brass is completely unnecessary. Sinclair has a little plug gauge that'll show you exactly how long the chamber really is. That 22-250 brass will most likely wear out and still never need trimming.

2)Don't crimp. There's no need to. The 22-250 doesn't have near enough recoil to even be a factor. A good .002-.003" neck tension is all you'll ever need worry about. And I can think of reasons why crimping could screw up accuracy.
 
Just a heads up if you do crimp your bullets you have to trim the cases every time you re size the case.

I only have bolt action rifles and an AR and I do not crimp for any of them. The bullets I use do not have a canular for crimping.




DAB
 
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Quote:Just a heads up if you do crimp your bullets you have to trim the cases every time you re size the case.

Yep, and trim new brass before you load it. That ends up being a lot of work, and I never saw any benefit in my rifles (other than the 30-30).
If you ever pull any .22 bullets with an inertial puller you'll see that they're not going to set back from recoil. The ratio of neck surface to weight is huge, and the recoil is mild.

You get up into heavy, fat bullets and that changes, you may need a crimp into a cannlure on those.
 
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Crimping is a necessity on heavy pistol rounds, straight wall rifle rounds, elephant loads, etc.
On most all bottleneck rifle rounds crimping is pretty much guaranteed to lessen accuracy.
You will never see a crimp in any benchrest competition or in most any other competition that pays prize money. People shooting for money will do anything that gives them an advantage and they never crimp.

Jack
 
I always crimp for my AR just as a safety thing for me! I always take new brass and make the my plinking round and then after they have been used once for plinking I will use them for my hunting brass! I know a lot of guys that swear by the crimp die and I also know a lot that do not use it! Everyone will tell you both ways, its kind like powder try it, if you like it use it, if not stop crimping.
 
I crimp my pistol rounds and my 223 and 308 that will be used in my semi autos. I use the Lee FCDs - I tried crimping other ways, but found I get the most consistent crimps from the Lees.

Good luck
 


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