Do I need a crimp?

[bbearhntr]

So I would like to load some .270wsm rounds for my winchester SXR semi-auto. From what I've read these rounds sould be crimped, right? Can you crimp an AccuBond? I thought the bullet needed to have a cannelure or crimping groove. I have a set of RCBS FL dies and from reading the instuctions I get the feeling I am only able to roll crimp with them. Is this appropriate? I would like to shoot the 130g Accubonds. A little direction from you experienced reloaders would help me a great deal....Thanks!

 

[DrMike]

You shouldn't need to crimp. If there is no cannelure, you do not want to do a roll crimp. If you choose to crimp, buy the Lee Factory Crimp Die and give a taper crimp. If the neck of your case is sized properly, you shouldn't need to crimp, however.

 

[Ridge_Runner]

of all the rounds I load the only ones I crimp are the 348 win. and the 458 socom, I crimp nothing using pointed bullets.
RR

 

[barthowes]

+1 for what Drmike said
I used to crimp all my rounds with the LEE factory crimp die. recently I had to pull a few of my bullets that I didn't crimp yet and I had to hit the puller/hammer so hard I thought the plastic would break. a Properly size neck gives A LOT of tension. but on the other side of it, you can't go wrong by using the lee FCD.

 

[Guy Miner]

I'm not familiar with your semi-auto rifle.

Normally I don't crimp bottle-neck rifle cases, but if your rifle slams the cartridge forward into a feed ramp real hard it MIGHT cause the bullet to set back into the cartridge case. That's not a good thing, so a crimp MIGHT be necessary.

I'd load a few dummy rounds, without powder or primer, and cycle them through the rifle, letting the bolt slam them forward into the chamber. If the bullet sets back, perhaps a crimp is in order.

Regards, Guy

 

[JD338]

I do not crimp bottle neck cartridges. I only crimp 44 Rem Mag and 45-70.
You will be fine with out a crimp.

JD338

 

[bbearhntr]

Thanks for the info guys!

 

[bbearhntr]

So I went to the range yesterday to try out some of my hand loads with my Winchester SXR 270 WSM. I did not crimp any of the loads. I measured the folwing round with my calipers before I loaded the clip with two rounds. I fired the first round and then ejected and measured the second round that was carried into the chamber by the action. The COAL of the scond round was consistently .003 - .005 inches shorter after it went through the action. I tried this about ten times and always had the same result, the shell "shrank" after it was loaded by the action. Is this a reason to crimp? Can I crimp Accubonds or Balistic Tips?

 

[Guy Miner]

You really want to crimp - so go for it! :grin:

Generally works best with a bullet that has a cannelure rolled into the jacket, to accept the crimp.

Guy

 

[bbearhntr]

I dont really want to crimp I just am not experienced enough to know if i need one. I dont want to have a catastrophy happen. I do have a case of OCD maybe it is just flaring up with this heat we have been having.... :roll:

 

[FOTIS]

I crimp for handguns and levers only.

 

[JD338]

Are you saying the bullets went deeper into the case after yoou ran them through the chamber?
Are there any other markings on the bullet? Maybe some engraving marks where the bullet is getting pushed into the rifling?

My other thought is sizing. Are you full length resizing or partial resizing the case? If you are only partial resizing the cases, go another turn in with the die as the case neck does not gave enough friction grip on the bullet.

JD338

 

[bbearhntr]

Yes it appears that the bullets are now seated .003 -.005 deeper after runnig through the auto action. No rifling marks on the bullets. These are virgin Win cases that I full length resised, trimmed and chamfered right out of the bag. I just am probably worring about this too much but OCD has its days.. The rifle shoots VERY well all thing considered!

 

[corbin9191]

I crimp everything but my 7mm wsm.

 

[SJB358]

If you are worried about it, but the LEE Factory Crimp Die like Mike suggested. It won't hurt a thing and put a light crimp on your bullets. If they shoot worse than your current loads, you will know that nothing is the problem. If they shoot better, well, you only spent about 10.00 on the die for peace of mind! Scotty

 

[negeorgia]

From Lee's instructions:

"Bullet Seating Die
"Screw the bullet seating die in until you feel it touch the case mouth. If no crimp is desired, back the die out 1/2 turn. If a crimp is desired, turn the die in 1/4 turn. The bullet must have a crimping groove or it cannot be crimped. Case must be trimmed to same length to provide a uniform crimp."

I post this because when I started rolling my own, by the time I was ready to smoke 'em, some were not as long as they should have been. The bullets were tight enough that I couldn't dislodge them by hand but apparently I had bumped them at some point enough to move some of them just a bit. There was a guy at the range who appeared to be an old pro (he was shooting multiple .223's through the same hole) and I struck up a conversation with him. He said you usually don't need to crimp but then you have to be careful how you handle them. He said if you're gonna hunt with them, a bit of a crimp can help because you will be putting them in the rifle and taking them out multiple times and otherwise handling them throughout the season. And this is the reason why the factories crimp them.

The bullets I use either don't have cannelures or the cannelures are not where I want to 'crimp' them. As I recall, I probably turned the die in about 1/8 turn, hoping to tighten the case neck's grip on the bullet just a little bit. And it seems to work okay. I have had no more displaced bullets except for the one I dropped on its nose.

Lee's instructions for their Factory Crimp Die states that no crimping groove is needed because the FCD forms one while crimping.

It sounds like you have determined for sure that the action of your semi-auto is bumping your bullets out of place. .003 to .005 is no big deal but if it happens to significantly compress one (and there's no way you would know it), that could create an overpressure situation. I would crimp.

 

[Guy Miner]

Keep in mind guys, that although he's shooting a cartridge normally found in bolt action rifles, his is a semi-auto - and the cartridges are subject to being slammed forward... winchester SXR semi-auto

I think a crimp might be worthwhile - at least to try.

But first I'd shoot some of the non-crimped loads at a target, say 300 yards away, and see how the accuracy actually is.

FWIW, Guy