300 WM. Crimp or not to crimp?

[West Calamus]

The only crimp I have ever used is the Lee Factory Crimp die, and have found that it has helped accuracy in several factory guns. I plan to use it for fireforming loads for my 284 and 223AI, but once I start load development I test with and without the crimp to see which gives me the better accuracy. Also, use a very light crimp with the Lee die. A crimp seems to help by evening out pressure needed to start the bullet, and it doesn't take much to do that. I will say, that die can really crimp down hard, even with bullets that lack a cannelure, but heavy crimps have always degraded accuracy.

thx for the input cs

 

[West Calamus]

How far into the case mouth is your end seating depth, this is the question??

If you have the projectile seated towards the land so far you have minimal grip then yes it may help.
But I am talking 25% or less the length of the case mouth.

I have never needed to crimp, even when seating a .22-250 just a few millimetres into the case mouth.

With correct neck tension even a few mm is enough but yes it would depend on the amount of recoil the rifle produces.

I know from other things I have read where people are loading for say 30-30's that many people that played with crimping found it did improve accuracy.

I dare say this just changed the pressure level to influence the accuracy node, but then again they have to crimp due to the tube magazine where as you don't need to.

My original problem was lack of magazine length and found that I would be seating bullet with part of neck seating on ogive. Remedied that by extending magazine box and now can seat bullet cylinder on all .264 inches of the neck. Jump will be controlled by my gunsmith throat reaming Shilen barrel to .010 to .012 jump . I like the slower burning powders as they seem to have less sharp recoil in the 25-06 and 7mm-08 loads I use. One of my goals on this build is manageable recoil. So back to the original question will I have enough resistance for a slow powder to more fully burn before bullet starts to move? Yea I know that I'm way over thinking this whole scenario. Just make up different loads and coal's and hit the range and the chips will fall where they may. Thanks for all the reply's. I appreciate it.

 

[palerider3]

You're way overthinking this. If you have correct neck tension, there wouldn't be any reason to crimp. Measure your brass and use the right bushing in your dies. I played with the Lee factory crimp die a long time ago before I figured out neck tension. After I started using quality brass I've never used it again for a bolt action or even for the ARs. If crimping is helping your 100 yard groups you probably need to figure out why and fix that and it'll help your SD/ES and your long range groups. No need to crimp unless you're loading for something hard on brass and bullets. M1 Grand ammo and tube fed guns get a crimp, but nothing else for me.

 

[West Calamus]

You're way overthinking this. If you have correct neck tension, there wouldn't be any reason to crimp. Measure your brass and use the right bushing in your dies. I played with the Lee factory crimp die a long time ago before I figured out neck tension. After I started using quality brass I've never used it again for a bolt action or even for the ARs. If crimping is helping your 100 yard groups you probably need to figure out why and fix that and it'll help your SD/ES and your long range groups. No need to crimp unless you're loading for something hard on brass and bullets. M1 Grand ammo and tube fed guns get a crimp, but nothing else for me.

What make of brass to you tend to favor if it is available?

 

[palerider3]

I've been using Norma in my 300WM for a few years. I hate the soft case heads but until recently there haven't been any better options. I'll be buying ADG to try after this hunting season. I prefer something with a harder case head like Lapua or Alpha brass in other calibers.

 

[Stevenstl86]

Bushing dies are definitely the way to go. Depending on the brass you use. I use 2-3 thousandth smaller bushing than the loaded round of the brass your reloading. I have even gone as far as resizing just half the neck with SD of 2 and ES of 6.

 

[wbm]

I would not bother crimping.

FWIW. Decade or two ago Lee and Speer got into a real spat over whether crimping improved accuracy. It became so heated and bitter that Lee finally issued a statement that said they could no longer recommend Speer bullets.

 

[105amatt]

I've never crimper any 300s.

 

[ofbandg]

I have owned a couple of hunting rifles where the new chambers weren't polished up after cutting and a sharp edge remained. The case mouths would sometimes catch the edge and deform slightly on feeding so I switched to crimping into a cannelure to solve this. Accuracy usually wasn't affected. A few times in the past I crimped heavy recoil rifles where I could see the bullets being knocked deeper into the case from contact with the front of the mag but it's rare nowadays as bullet and case specs are more uniform. Overall I don't crimp unless there is a specific problem.

 

[freddiej]

I do not crimp any of my hunting loads. they all work well and never fail me. My 300 just hates crimping, the slugs do too. I get better performance, accuracy, and dependability with out crimping. why mess with excellent results?

 

[Clem Bronkoski]

I used the Lee crimp dies also. I used them in 7-08, .270 and 30-06. I found increased accuracy in the 7-08 and .270 but not in the 06. The .270 had the most improvement with groups shrinking about 40%. Less with the 7-08 and no change with the 06. Now these are with standard sporting rifles not any LR ones. The Lee crimp dies aren't expensive so it wouldn't hurt to try.

 

[Swordslayer1]

No Crimping here....Never had an issue

 

[Calvin45]

Played around with crimping in the first year or two of doing this. Didn't find it hurt anything but also found it didn't help and is unnecessary. My approach then is to not do it initially. If for some reason a bullet will not shoot well crimping is near the back of the list of things to try but it is on the list. If the Bullet has no cannelure or grooves then it doesn't get crimped for any reason whatsoever. Plain Jane flat base interlocks seem to like crimping in my 270.

 

[naja302]

I doubt that you need to crimp.

I do crimp loads for one of my 300 win mags though. I had trouble getting the 181g hammers to stay put with a compressed load of H1000 but it was super consistent and accurate even with the crimp so that's what I do.

I also crimp loads for my 358 STA cause it kicks like a mule!