Crimp or no crimp????newbie needs info

[BIG A972]

I just started reloading.......I have seen alot of people stay if you are using a semi-auto then you need to crimp......but others say no need.

Whats the low down. Please tell me why you do or do not crimp.

[BIG A972]

I am reloading for an ar-15, 9mm and 40s&w.

[btroj]

I would put a slight crimp on them. Enough to prevent the bullet from seating deeper when feeding from the magazine. You also need to make sure to remove the belling from the mouth of the pistol rounds.

This is like asking if broccoli is good. You are going to get a wide range of answers. And I hate broccoli.

[462]

I am reloading for an ar-15, 9mm and 40s&w.

Don't have any of those, but for .45 ACP, I use just enough taper crimp to allow the cartridge to chamber.

Most likely, experimenting will give you the best answers, for your particular guns.

[MtGun44]

For semiauto pistols you need a taper crimp to ensure full chambering. Remove the barrel
and use it as a gauge to set the seating depth and degree of taper crimp. Ideally, taper
crimp should be done as a separate operation. Inadequate or no TC is the
most likely cause of failure to feed in .45 ACP. The round should seat in the
dismounted barrel with no more than 1 lb fingertip pressure, dropping all the
way in flush is ideal.

For .223, you want a cannelured bullet and the Lee factory crimp die is recommended to
get a good crimp. Another point is that the .223 is extremely sensitive to case length,
DO NOT skip the case trim step. I have personally witnessed three .223s blown up by
over length cases. (None with my ammo!)

Note that the Lee pistol factory crimp die is totally different from the rifle factory crimp
die. I recommend the RIFLE version and suggest that the PISTOL version has caused
some issues in some situations with reducing the boolit size inside the case.

Bill

[bobthenailer]

I would recommend taper crimping all auto pistol rounds that headspace on the front of the case.
I could give you some taper crimping demsions but i would have to look them up if needed .
IF so plesae leave me a PM. Bob

[BIG A972]

So far I have been crimping them just wanted some in site on what others are doing or not doing.

[Markbo]

.... Remove the barrel and use it as a gauge....Bill

Bill.. for what possible reason do you need to remove the barrel to set seating depth and crimp?

Mark

[MtGun44]

To get the seating depth correct and to get the TC amount correct for reliable feeding.
You want a cartridge the will drop freely or with a very slight push all the way into the
chamber. Just because it will jam in with the slide slamming home, you won't really
know if it is oversized, or the neck dragging or the boolit hitting the rifling until it
jams.

Bill

[Char-Gar]

You taper crimp rounds for the auto pistol and roll crimp rounds for sixguns.

[WILDEBILL308]

You must use a taper crimp on auto loading pistol rounds. You will use a roll crimp on revolver rounds to prevent them from moving under recoil. You should also check that your expander is not too big. Neck tension is a big contributor in keeping the bullet in place.
I would by a case gage to check my loaded ammo. This gage is made to SAMMEY specks for the caliber. If it goes in the gage properly it should fit any chamber in that caliber. They are available from several sources. I bought some from Dillon and they worked well.
Bill

[Markbo]

Thanks for the response Bill. I have never had to remove a barrel to accomplish that. OAL maximized by the magazine usually, the rest is bullet seating depth. I have tinkered with that to maximize accuracy (sometimes amazing improvements with little increments in seating depth) using a Stoney Point tool or a bullet in an empty case, always with the barrels right where they always are.

[John 242]

I think what Bill is alluding to is similar to what I do with my 1911.

I remove the barrel and use it as a gage to check my loaded ammo. By dropping the loaded round into the chamber I can check whether it chambers easily and if the OAL is correct. The bottom of the case (the rim) shouldn't protrude past the barrel hood. If the cartridge doesn't freely enter the chamber, then most likely it needs more of a tapper crimp.
(I forget what the recommended crimp dimensions are, but I find it really hard to measure crimp with calipers and this method works great regardless.)

I found out the hard way that crimp matters when my TC die lock ring had allowed my die to turn. I was at a match and I kept getting failures to feed. The slide wouldn't go fully forward, but only by a tiny amount. It was slightly out of battery enough to prevent the gun from firing. All 200 rounds were like that and it made for a long day and a terrible score.

Now, before a match, I chamber check ALL of my rounds.
I also invested in some Wilson case gages, but I mostly use the chamber method.

[mdi]

This is another question that comes from using the term "crimp" when it comes to reloading for semi-auto ammo. I prefer the term "de-flaring" as very little taper crimp is actually used, just enough to remove any flare used to ease bullet seating, if you can see any crimp, it's too much. Over crimping can lead to probs. too ( deep chambering, etc.). Neck rension should be enough to hold the bullet in place during recoil and feeding.

This is a fairly common question and I think the new reloader can be helped if he/she doesn't think if this operation as "crimping", but rather "de-flaring" or straightening the case mouth.

Hey, jes my .02...

[MtGun44]

For me, it is definitely a taper CRIMP, not just removing the flare. Never had any issue
that could be traced to excessive taper crimp, but THE most common failure for a new
semiauto reloader in 30 yrs of mentoring new IPSC shooters was failure to or inadequate
taper crimp. Over the years about 8 out of 10 'jamming' problems with a novice
reloader were complete lack of or inadequate taper crimp. LOA accounted for the
next largest group, with high primers in the mix, too.

Bill

[thenaaks]

lots of good replies. but in super layman's terms: yes you need to crimp, so that the round will chamber fully, and so the boolit (or bullet, whichever you're using) will not get forced into the case as it bumps against the feed ramp. if you're using jacketed then the lee fcd will work fine. if shooting cast, then skip the fcd, and just make sure you're getting enough crimp. i do this by measuring the oal, chambering a round, then ejecting the round. re-measure to make sure it's just as long as when you started.

[Willbird]

I do not think taper crimp is a "MUST" for semi auto rounds. RCBS sold a bazillion die sets for semi auto cases, and reloaders shot a blue kazillion rounds without ever even knowing a taper crimp existed.

Yes it will over all improve function of rounds, but I never had a malfunction issue with 45 acp ammo lightly roll crimped just to remove flare, not even once.

IPSC is a LITTLE different than target shooting and just plinking around.

As for semi auto rifles, you can get by fine with no crimp.......again I loaded a dump truck of 7.62 nato as a junior shooter with J word bullets from DCM.....not one was ever crimped...they worked great .

The neophyte will typically flare too much, and crimp too much and too often.....not vice versa.


Bill