45 ACP crimp

What crimp do you prefer for your 45 wad loads. I see a lot of people say .470 and forget it. I have experimented a little (off a sandbag so no absolute results) and my new 45 with a Bar-Sto barrel seems to slightly prefer a tight crimp of about .462. This is with 200 and 185 grain LSWC using 3.8 grains of Bullseye or VVn310. My spring was kinda on the threshold for function and I tried crimping some tight and function improved. I guess it takes a little more pressure to get the bullet moving. I have also seen some say a crimp this tight deforms the bullet. It seems the crimp affects the function more then the group size although the heavy crimp is a slightly tighter group. Has anyone done any testing on a ransom rest or a chronograph with different crimps?

Thanks for any help!
Mike

Most here like the .469-.470 crimp.......My gun likes that range as well with lead bulets...I use a lee factory die ,200gr Penn bullets and 3.6 Clays or 3.8 BE and my spring is either a 12 or 11 .....I tryed 185's same crimp with 4.0BE and 3.8 BE Accuracy wise I see no difference but my gun seems to like 200's better function wise.......there is a member here that did some testing in a RR with crimp.....and I believe he found a slighly losser crimp produced nice groups but if I remember right had some function issue's I think....I'm sure he will chime in if he wants......But all guns are different....Ive heard of people useing tight crimps......But most here like the try'd and true 200gr , .469 , 3.8BE loading......About the only issue I had with crimp was on the 185 Button nose bullets.....If my crimp wasnt right it wouldnt feed.......YMMV

ive ransomed many loads and.468-.469 works for all .452 size lead bullets, .451 FMJ's I take down to .467 But crimp is one of those things that no two people measuring the same bullet will get the same reading. I use a quality mitoyo caliper, just barely touching the ver.y highest point of the case. Anything more than .465 is bordering on bullet deformation in lead, but if your using to much pressure when checking a .469 can read .465 or even less Another way the old timers do it is to take a factory match round, put it in your sizing station and screw the die down on it till its a snug fit. I know one high master that this is the only way he will do it, never has he even checked it, it just works.

There are probably various ways to get to the same place. A little less powder and a little more crimp might be the same as a little less crimp and a little more powder.

The very first Kart I had installed on my wad gun didn't shoot well until I tried a .463 out of frustration with every other combination @ 50 yards. So don't exclude trying it.

The last 3 I've had built all liked a .469-.470, a bit more in the traditional crimping range. But, I also use a bit softer BN hardness now, and I'm sure that comes into the equation.

All loads developed on the Ransom rest.

I have been reloading 9mm for my service pistol with no crimp at all (115 gr FMJ Hornady, 6 gr Power Pistol, 1.12 OAL). I will be reloading .45 very soon. Do I absolutely need to crimp my .45 reloads?
Should I be crimping 9mm? I have seen so many discussions about this it makes my head spin.

9mm is a whole different game, if you dont crimp a 45, you will never get off a shot.

Hi Guys, We all know there seems to exist a bit of controversy about crimps

deeper than a certain amount, will deform the bullet. Well that is true, but

how much of the bullet is deformed seems to be overlooked. The most accurate

50yd load that I ever shot through my Gold Cup(bought in 1972) was someone

else's load that we tested in a Ransom Rest. Those bullets were crimped

.462". I just checked some of my recent loads that I crimped .466" at the case mouth.

At .050" down from the case mouth, the measurment is .468"; by .10" the crimp ends

and the case is back to .470". The bullet is really only pinched for a .050" length. The

shoulder ahead of the case mouth is not deformed, and neither is the bullet beyond

the affected crimp zone. my Dardas H&G #130 driving length is .320"s. Roughly 84%

is intact. Maybe this is the reason that accuracy is sometimes found at heavy crimp

measurements. My humble conclusion is that crimping doesn't deform the bullet as

much as we thought it did. Dry thoughts of a dry mind, I guess;

Tony

Hmmm, interesting...I always used my barrel as a gauge, as shown here:
My rounds are crimped .4715" exactly and they sit absolutely flush with the barrel when chambered.
Am I doing anything wrong?

Java,
The only thing I do (mainly because someone smarter than me suggested it), is seat my bullets so the overall length is just slightly (2-3 thousanths) shorter than flush with the hood. The reason given, which made sense, is if the face of your slide gets really dirty and a crud buildup you may have feeding issues.

I try never to let mine get anywhere near that dirty, but it's one of those things you do just in case.
Al

Well, my point is, the .4715 crimp seems to be much more than what people are suggesting here (.462, .468, etc), so I'm wondering if there's anything I should do differently. My gun is based on Kimber and I used the stock Kimber barrel.

No .471 is less crimp than many suggested, if it feeds then shoot it, but with a tighter crimp you will get a better and more consistent burn of the powder. Do you get a lot of muzzle flash, dirty residue in the gun and on the cases, all these are signs the crimp is too light in a 45.

Java,
As long as they feed reliably in your pistol, there's absolutely nothing wrong with the amount of crimp you're using. .4715 is a mild crimp that won't overwork your brass.

I usually use a .470 for my long line loads and .468 for short line, just because I'm overly paranoid about reliability in sustained fire and I use a light load of 3.5 gr Clays with a H&G 130 for the short line and 4.3 gr WST with a H&G 68 for the long line. I use a 13# spring (slide mounted Ultra Dots) for outdoor and 11# for indoor. Sometimes at the end of an outdoor match the last couple of rapid fire strings don't lock the slide back after the last shot, and I get nervous. Thinking of bumping the short line load up to 3.8 for peace of mind. It shoots as well as the 3.5 but would be a bit more oomph to cycle the slide at the end of a match.

100% reliability with accuracy is the benchmark for amount of crimp in my book.

Yes, so far I have absolutely no issues with this load - .4715 crimp, 3.8gr Bullseye*, 200gr LSWC Penn bullets. My spring is very light, about 9#, and slide has the clark rib ultradot mounted on it. No problems with accuracy either, last weekend I shot 4X in a row @50 yds (never happened to me before The gun gets dirty, yes, but I clean it after every shooting session.
(*) I use 4.0 disc on my Lee press, but it is actually between 3.7 and 3.8 when measured on digital scale.

If things work, just concentrate on shooting