Home Forums Hunting & Shooting Ask The Gunwriters To Crimp or Not, Projectile-writers?

I've been running some experiments with my magnums (257 Wby, 6.5x300 Wby, 375 H&H, 416RM), crimping and not. I don't see any difference in accuracy, and I'm not beating up the tips of the bullets in the magazine. So what?

Some people swear you must crimp, others say it isn't important (or needed).

What do the projectile-writers think about crimping, when there is and is not a cannelure? What about adjusting COAL with bullets like Barnes that have grooves so you can crimp in one of their grooves?

I never crimp anything that I load.

I crimp handgun loads, 30-30 loads and shotgun shells. Nothing else. I have considered crimping Varget .223 loads but I just swithced to CFE-223, made better sense.

Edited to add:

I crimp the round I do simply as a matter of cheap insurance. Heavy hand gun loads are already puhing things and have little tolerance for bullet movement. I have seen 30-30 bullets move from cycling through a rifle. Compressing Varget enough to get some published .223 loads into the brass has shown me that the compression can push the bullets back out every now and again.. Seating depth tends to be very critical with monos and a moving bullet makes for poor accuracy. I actually switched to other powders just to get away from the issue. That says a lot because I love Varget.

This is coming from a deer hunter's perspective. Someone else might chime in with a different opinion that has gone up against dangerous game.

The only time you NEED to crimp is when you've got a situation like a tube-fed 30-30 where the rifle might compress the loads while they are in the magazine. If you were going to single-feed them, even 30-30 wouldn't NEED to be crimped.

With pistol cartridges, it's probably a good idea to crimp. I can't think of a batch where I didn't crimp. It's a small cartridge, and having a bullet slide ,01" can dramatically increase pressures.

Now that we've got those two situations out of the way, let's look at the rest.

Take your average centerfire rifle cartridge. If you are single feeding them at the bench, there's really no great existential NEED to crimp. In the field, they can probably ride safely all season in the mag, and come in and out of the chamber without disturbing the bullet. However, crimping might improve a situation where the load was producing inconsistent pressures. It is one of the tricks a loader has in his bag.

The downside to crimping is that it puts more wear and tear at the case mouth. Theoretically, crimping reduces the number of loads you will get out a given piece of brass. With expensive, exotic brass, that could be a factor.

In general my opinion would be that one should crimp only when necessary and provide the least amount of crimp required. Crimping into a crimp groove is usually preferable. However, the Lee crimp dies supposedly allow you to crimp even if there is not a groove. Somebody else besides me needs to chime in on this.

When I was working up my deer loads in 35 Whelen, I tested a few powders. One was H4895 and another was BL-C(2). I found BL-C(2) provided higher velocities, but H4895 had more consistent velocities. I tested BL-C(2) with a light crimp and found there it did provide a slight improvement. However, it was easier to stick with H4895 without crimping. The Remington 7600, AKA The Whelenizer, provided venison for the next 10 seasons. The recoil was considerably higher than anything else in my deer arsenal, but I never found a reason to crimp.

I NEED to say one other thing about crimping, and that is how to do it. In general, I find the Lee Factory Crimp Die to be the best way of applying crimp. I have mostly RCBS and Redding dies, and when I played with using the crimp feature of them, it invariably lead to trouble. That was until I hit upon the idea of doing bullet seating and crimp as two separate operations. First, I used the bullet seating die to seat the bullet to its proper depth. Then, I backed off the bullet seater plug and reset the die to use the crimping feature and ran them through again. I know others on this august forum who do it this way.

There are only three reasons to crimp in my own experience
1. When shooting heavy revolver loads...The recoil can actually "pull" the bullets out and lock up the cylinder if they are not crimped.

2. When using a tube fed gun such as many lever actions. The compression forces of the tube might push the bullets back into the case

3. When shooting heavy double rifle loads....the recoil can again pull the bullets from the case.

If, by experimentation, you discover an accuracy advantage in crimping, by all means do so.....but It's never been the case for me

I quit crimping .30-30's years ago, after putting uncrimped rounds in a typical lever-action tube magazine for several shots, and finding the bullets never moved.

I did crimp .348's back when I had a Model 71 Winchester, but don't know if it made any difference there either. Didn't bother with crimping after acquiring a .33 WCF a few years ago.

I do crimp .416 Rigbys, but haven't done any tests to see if makes any difference. Quit crimping .375 H&H's a long time ago, mostly because in my rifle the standard powder charge is so compressed there's no way for bullets to be pushed deeper if they hit the front of the magazine box during recoil.

Elmer Keith once noted that case-neck tension on the bullet has FAR more effect on keeping bullets in place--and accuracy--that crimping, even in heavy revolver loads.

I did an experiment a few years ago when I first started loading. I seated a bullet in an empty 30-06 case and cycled it through my Browning BAR something like 20 times. I put it in the magazine, pulled the bolt back and let it slam closed. I think it moved a thousandth or so, not enough to matter so I never crimped anything except 30-30's because everyone says I am supposed to.

If you read Richard Lee's book, his sales pitch for the FCD is pretty interesting. IIRC, he makes the case that that loaders have long known that seating bullets right on the lands allows for more pressure or more consistent pressure to build in the case which helps with accuracy, and also states that since the ammo companies have to make ammo to Saami specs, they crimp and even go so far as to glue bullets in place in order to achieve the same effect. Its not so much for the purpose of keeping the bullets from moving.

Whether he is right or not is way over my pay grade.

Crimping is an inexpensive option that some reloaders will find benefits their situation. Of course, the only way to know is to test.

I found that crimping helped with several of my surplus rifles. I noted less shot to shot variation versus uncrimped in many of my surplus rifles. There was little, if any difference in rifles with chambers in good condition. I checked several 303s and a couple of 7.62x54Rs.

Two things I discovered shortly after the Lee crimp die hit the market. The first was that most people apply too much crimp. I found that by screwing in the die bit by bit, I could detect when the petals made firm contact with the case neck. For me, this amount of crimp was all that was needed. You want to ensure consistent contact - not crimp so much that it deforms the bullet.

The second thing is looking into the die from the top. When you feel the crimp die making contact with the bullet, the petals will still have plenty of gap between them. The less gap, the more crimp you are applying. In most cases, this would be too much.

Like sizing wax, a little crimp goes a long way.

i crimp all my reloads rifle & hand gun .it gives me a sense of cofidence .it gets bounce around in the woods a lot

And there's nothing wrong with that!

I reload all my centerfire ammo and have for quite a while.. I do all my bullet seating with a Lee hand press so I feel that I have a better sense of how much neck tension occurs from round to round. I find that often there is a variance in bullet seating resistance / neck tension among cases in a given batch due to neck thickness, bullet diameter, etc. I take the extra step of using a Lee Factory Crimp Die to apply a light crimp for consistency and peace of mind particularly with high recoil cartridges. Does a light crimp affect performance of a 60,000 psi round? Likely not. Happy Trails

I'm more than happy to accept this as it's written.....I've never owned a model 94 or 336 but I have owned a model 92 in .25-20....the bullets had to be crimped in that gun as they were pushed back by the compression spring......and I mean WAY back! I also used a 60 grain bullet which has quite a bit less contact with the case walls than the more conventional 86 grain load.

It just goes back to the old statement....every gun is an entity unto itself.

It's very possible that .25-35 rounds would not require crimping and several others as well.....I can't speak for the .218 Bee or .32-20 as I have no experience here either....that said, I'd not purchase a tube fed gun and expect to not have to crimp loads.....and besides....it's not at all difficult to do!...that is assuming one has fairly uniform case lengths.....and that can (in some cases) be harder to do than the actual crimping process. For this purpose, I highly recommend the Wilson case trimmer......a very fine tool.

i use the lee crimp die on all cal. i load for

Not a “projectile” writer, my 2 bits,

44 magnum Revolver - yes

All else - no

I crimp sometimes. Almost never with jacketed bullets. Usually with small charges of pistol powders in rifle cartridges with cast bullets, I crimp, and crimp heavily.

I roll crimp revolver loads (heavy 44, 454 and 475 Linebaugh loads get Lee's FC treatment)
I taper crimp auto pistol loads
I FC auto loader rifle loads (AR, Garand...)
I FC or roll crimp heavy recoiling loads (416 Wby, 9.3x64, some 358 Norma...)
The other round that gets a FC is a 300 Savage in a small ring Mauser. The neck is short and the barrel is throated. There is very little bullet being held by the neck when a 150gr is loaded out to within .010" of the lands.

All else I leave alone and don't crimp.

I did acquire a 204 Ruger FC die as a package deal at an auction. I posted and sold the die to a fellow shooter who said it corrected the problems he was having with his 204, and made it more accurate (consistent). I do not know if his 204 was a bolt gun or AR.

Barnes bullet company on some of their copper bullets say to crimp,example of bullet size is 130 gr. 30 cal. and to be honest those bullets do shoot better crimped. I own about 25 different cartridge lee crimp dies,nice to crimp some hunting cartridges so they don`t fall apart. I have notice some of my cartridges do seem to shoot a little better. but I would have to use these crimp dies more to know for sure,which by the end of next winter 2018-2019 I will know more, but remember I don`t write books and only do this for fun and maybe my findings from my tests may not be the answer for all cartridges. from what I do know any tube fed centerfired cartridge lever rifle from now on I will neck crimp if I would have to use a lever rifle with tube feed, its still just a personal choice for a hand loader.

When loading for my .44 Mag revolver I found crimping helps slow powder burn more consistently and completely when loading down to where set-forward isn't a problem. In that case a heavy crimp worked better than a light crimp.

Only crimped in rifles for semi-auto.

I crimp revolver ammo and cast bullet rifle loads, never crimp jacketed bullets in rifle cartridges.

pete53,

That's interesting about Barnes and crimping, but the only thing I've found on their website about crimping is this, in Frequently Asked Questions:

"Do you recommend crimping your bullets?"

"We usually don’t recommend crimping our smaller-caliber bullets. However, if you choose to do so, a light crimp is best. Heavy caliber bullets (.375 and up) for large game require a heavy crimp, as do most revolver and lever-rifle loads."

Did you find the info somewhere else? I've always gotten excellent accuracy with the 130-grain TSX/TTSX in a variety of .30 caliber cartridges from the .308 Winchester up to various magnums without crimping.