# Question about crimping 300 blackout loads



## THE JAMMER (Aug 1, 2005)

As said on another post my most recent project is a 300 blackout pistol and reloading for it. My question is regarding crimping. 

I rarely crimp very often, but when I do I always back the die out for my first load, and incrementally lower the seating pin until I get my seating depth correct. I then back off the seating pin, run the case up into the die and screw the die down until the shell holder makes contact with the case. I then lower the case, screw the die down about another 1/4 to 1/2 turn, lock it down with the allen screw, and then run the case up, thus crimping the neck mouth. Then while leaving the case up, I lower the seating pin down until it contacts the bullet, then lock it down. Then that die is now ready for reloading that round.

That gets me close so that when I put the next case in I can just run it up in one motion and crimp and seat the bullet. The seating depth will generally be a little off and I have to make a few minor adjustments on it to get it correct.

Now I hear a lot of guys talking about getting a separate Lee crimping die, and doing it in two different motions. Seat the bullet in my RCBS die, and then put it into the Lee die for the crimping. I have done this with my 44-40 reloads because the case mouth is so thin, that if everything isn't just perfect, it will crush the mouth. But I don't think that is a problem with 300 blackout brass.

OPINIONS???? Is it worth the extra effort?? The crimps I get with the RCBS die look to be smooth. What extra am I getting using the Lee die??


----------



## artys_only (Mar 29, 2005)

Jammer are you using the Rcbs seating die with the taper crimp option ? That what I odered , interested in how to set it up .


----------



## THE JAMMER (Aug 1, 2005)

artys only said:


> Jammer are you using the Rcbs seating die with the taper crimp option ? That what I odered , interested in how to set it up .


Ok Artys now you got me going. I have been reloading for over 35 years, but I have never really been tooooo knowledgeable about crimping, because I didn't do a lot of handgun stuff. Just 30-06, 7 mag, 308, non cannelures bullets, etc. so I didn't worry about crimping.

First of all I did not know there was a separate RCBS die with the TC option. Mine does not have it. In some research I have just done it seems most dies, RCBS included, have a tapering feature built in, and the one source I saw said that although unless you have a dedicated TC taper crimp die, that it will give a roll crimp. However, it went on further to say that if, in one of those RCBS non tc dies that if you screw the down just barely below where it makes contact with the case you will get a roll crimp, whereas if you screw it down a bit further you will get somewhat of a taper crimp, although you can damage the bullet if you go too far. A taper crimp appears to be only about a 7 degree angle of crimp. Not much. Seems to just tighten the neck's hold on the bullet to prevent set back on recoil.

I am using mostly cannelures bullets, which it seems I am ok using my non TC rcbs die and just roll crimping into the cannelure. It seems, however, if I were to use non cannelure bullets, I might be better off getting the dedicated Lee taper crimp die, or I might should have originally gotten the TC RCBS die, which I did not know existed until you brought it up.

Confused?? Yeah me too. Seems like bottom line is roll crimp for cannelure bullets, taper crimp for non cannelure bullets. If you use a non TC die on a non cannelure bullet, it seems you can still crimp it in a bit to hold the bullet better, but don't go too far.

Really need some gurus on this. C'mon Ernest, Charlie, etc. where are you?


----------



## Ernest (May 21, 2004)

Sorry, I am no help on crimping issues. I don't crimp any rifle rounds. 

When I crimp handgun loads, its primarily a slight roll crimp on .357 rounds (lead semi wad cutters at .38 special type speed) fired from revolvers. For taper crimp rounds like 9's or 10's, I believe I'm using dies that only taper crimp because they are designed for rounds that headspace off the case mouth.


----------



## artys_only (Mar 29, 2005)

These are the dies I just purchased jammer ?

I believe they work the same way you have been doing it .

http://www.midwayusa.com/product/26...onfirmation-_-OrderConfirmation-_-ProductLink

Let me know what you think ?

Sent from my iPhone using Tapatalk


----------



## andre3k (Dec 3, 2012)

For semi auto I usually shoot for .003-.004 in neck tension. That's enough neck tension to not worry about bullet setback with non cannelure bullets. I just recently tried a lee FCD and it seemed to do the job okay. I usually use the seater / roll crimp dies for stuff like 38 special and 357.


----------



## THE JAMMER (Aug 1, 2005)

artys only said:


> These are the dies I just purchased jammer ?
> 
> I believe they work the same way you have been doing it .
> 
> ...


Looks like you got the right dies #22407. I got the # 22401 without the crimp. My screw up. Just ordered the lee crimp die. Only about $13 with amazon prime. Here by thursday. will advise.


----------



## CHARLIE (Jun 2, 2004)

Sorry no help regarding taper or roll crimping. My pistol experience is 45 auto that seats on case. So never roll crimped. Not having any experience or ever looking at a 300 blackout I just kinda assumed it didnt have a shoulder. I guess it must have a little huh ?
For some reason I just pictured a straight case. Guess I better go look.

Ok looked and see a small shoulder but the display showed like 5 different cases and called em all 300 blackout. I gotta do more research. LOL

Sorry but what I read it doesent "light my fire " LOL. Sticking with my old GI 30 carbine for a truck gun and short range.


----------



## horned frog (Nov 9, 2008)

Crimp the heck out of those 300 BLK reloads. A strong crimp "may" prevent bullet setback and keep the bolt from closing should one accidentally end up in a .223/5.56 chambered gun.

Of course, all precautions should be taken to keep from mixing up the ammo, but mistakes can/do happen and redundant safety measures can sometimes save the day.


----------



## JuanGrande (May 29, 2010)

I've had good luck with the Lee Factory Crimp Die, use it on all my 300 BLK loads. I was noticing some strange muzzle velocity differences with my 220gr subsonic loads that I eventually attributed to bullet set back. Was getting very noticeable vertical stringing on target at 100yds. So I took a chance on the FCD for $15, loaded a few rounds and bingo, no more problems. 

Never thought about it as a safety measure to prevent chambering in a .223/5.56. Something to think about.


----------

