is this ok accuracy?

Status
Not open for further replies.
The reason for crimping a rimless cartridge is to remove any flare from the mouth after seating the bullet. A rimless cartridge like the .45 ACP headspaces on the mouth of the case, so you don't want to crimp too far, just remove the flare.

My SIG 220 has a pretty generous chamber, so it's not fussy. I don't know about the FNP, how tight it's chamber is. I do have some guns that have tighter chambers, and they won't accept a cartridge that has any flare left. So I do have to slightly taper crimp for this ammunition to be reliable in my autos. Most autoloader bullet styles do not have a crimping groove, so you won't easily over do a crimp, because the bullet supports the mouth, and you'd probably crush the cartridge before you'd get much crimp from the die. I often check that my rounds will chamber smoothly on one of my tighter chambers, just to make sure I have run them far enough into the crimping die. Just don't put a roll crimp on them like a revolver cartridge.
 
10-4 on the headspace/crimp for the ACP cartridge. One of the few things I am aware of :) both my Sig and the FNP seem to swallow anything without hesitation.

I was just wondering about the degree or intensity? of crimping on a soft lead or plated bullet. what i read made it sound like the softness would allow you to crimp too tightly and thus affect pressure buidlup as opposed to a true jacketed bullet that might tolerate more crimp pressure.

I think, for this batch of Rainiers, I am moving toward a load of:

Mixed brass
Wincherster Primers (CCI's were ok but gave more umph and higher velocities)
4.8-5.0 grains of either BE or HP38
purposely crimp very lightly.

Maybe make a few test batches and try the current crimp, then reset the Lee FCD to just 'kiss' the case mouth to about 0.471" (read that on line) and see what happens.

It is also an interesting thought that maybe I am doing some flinching or something due to bench resting. Common sense says BR should give you a more stable platform and more consistent results. But who knows?

there are Sooooo many variables. quite the task to sort them all out.
 
Ditto on the squibs. They can blow up your gun or hurt you, so address that first. What kind of press are you using? If you're using single stage, you have a perfect opportunity to quickly visually check every case before seating bullets.

The accuracy you're getting is "combat accurate."

Also, if you're going to try semi wadcutter bullets, be ready for feeding problems, especially if they are not plated. They're just not as reliable in modern guns.

Reducing the powder charge often increases accuracy, but it also decreases reliability. You may need to under-spring the gun so that it will shoot the soft, accurate loads reliably. Are you willing to do this for smaller groups? My advice is to pick one gun and make that your target gun. Be willing to work on that one. For me, that gun is my Ruger Mk. II Target, and I leave my combat guns stock and just load round nose plated bullets hot enough so that they are reliable.

Oh, that's another thing: cast bullets are slightly more accurate, due to their tighter fit in the bore, but they are a LOT dirtier. You'll have some lead fouling and a LOT more soot. Unplated cast bullets are lubricated, and the lube burns as the bullet is in the barrel and the flame is behind it. This means lots of smoke and more frequent cleaning.

So before you do anything, you have to decide how much trouble you're willing to go through for higher accuracy.

I accept combat level accuracy for the convenienct of easy, seldom cleaning.

Whatever you do, address the root cause of the squibs.
 
Got Lead? said:
The reason for crimping a rimless cartridge is to remove any flare from the mouth after seating the bullet. A rimless cartridge like the .45 ACP headspaces on the mouth of the case, so you don't want to crimp too far, just remove the flare.
Click to expand...

In my experience, it needs a bit more than this. Remember that when the round is being chambered, the first thing that happens is that the slide slams the round into the feeding ramp. If there's only enough crimp to remove the flare, this may push the bullet back into the case, and increase pressure.
 
On the squibs - I use a Lee turret press. I frequently take a case out and check the powder to make sure it is dropping the charge correctly. My guess is that I forgot to put the powder back in after i checked it.:mad:

That is a sobering issue though. once in a while I, or my son, might like to rip off a magazine full just for fun. going that fast, you might not have time to react to the sound of 'Pop" instead of 'bang' before pulling the switch again. Now that would be fun.

I agree I need to do something a little different to ensure proper powder each and every case. I will need to think about a process modification.

As for combat accuracy, I agree and i know that this is close enough most of the time. However, I also know that the guns can shoot much better groups without any more effort on my part, if I can dial in the right ammunition. I've used other's reloads and done very well. And certainly there are some great examples of accuracy in this thread in the beginning.

So I think I will continue to experiment and find something that is worthy of the inherent accuracy of the guns. Not for Bullseye competition or anything, but so that if the time comes and the need arrises, I will be absolutely confident of shot placement. That is really my main goal.

that, and to STOP WASTING SO MUCH MONEY ON FAILED EXPERIMENTS!!!
 
Modern handguns not reliable with lead semi-wad cutter?

That depends on the pistol make/model. M&P 45s, PT145s, and various 1911s (Kimbers, etc.) feed/chamber 200 gr LSWC loaded to 1.25"-1.27" OAL reliably.

For rimless cartridges, I believe the bullet is held primarily by neck tension from resizing the case and not from taper crimp. In fact, too much taper crimp with some brand cases will result with the case neck springing back out but not the "post sized" lead bullet causing the bullet to be seated deeper in the case when the bullet hits the feedramp from the magazine.

Even with the light taper crimp of .472" (.020" over the .452" diameter bullet), I can't move the bullet when I press as hard as I can against the bench top and feed/chamber reliably.
 
if you want the accuracy load, I would suggest starting at 3.8 grains of these powders and working your way up to 5.0 or so grains in .2 grain increments. Load 5 or 10 of each loading and bench them. Make sure your barrrel is clean at the beginning of each work-up. I'm finding 3.9 grains of BE works well with my 200 grain cast bullets, for about 750 fpsm and it functions the gun fine. Lead is lead, most of the loads you find in a loading manual, even the "starting loads" listed for lead loads may be above the accuracy potential for the bullet / powder combination. As you work up, you may find a second accurate load at higher loadings, I found this to be the case with 700X. You wil just have to experiment a bit, be prepared to go outside the box a bit, but don't exceed maximum listed loads.

You might slug your barrels to determine their bore diameter, my SIG runs a bit on the large size at .4525, most 45ACP's run .4510 to .4515. If you can choose the bullet diameter get .452's over .451's.
 
Jim Watson said:
May I suggest you concern yourself with safety and function before you start trying to improve accuracy. If your machine does not accomodate one of the mechanical powder checkers (I don't think the Lee will.) you simply MUST look in each and every case before seating a bullet to be sure it contains one and only one powder charge.
Click to expand...
+1. On the LCT there's no excuse for squib loads. You can certainly look in each and every case before you place a bullet. Nothing else is acceptable.
 
In my experience, it needs a bit more than this. Remember that when the round is being chambered, the first thing that happens is that the slide slams the round into the feeding ramp. If there's only enough crimp to remove the flare, this may push the bullet back into the case, and increase pressure.
Click to expand...

If you are suggesting that a taper crimp actually contributes to bullet retention, you are wrong.
 
918v said:
If you are suggesting that a taper crimp actually contributes to bullet retention, you are wrong.
Click to expand...

Again, it is my experience that has shown this. You can call me wrong all you want.

Just out of curiosity, what is it that YOU think retains the bullet in the case?
 
When you re-size the case, you're sizing the inside diameter to slightly less than bullet diameter. And with a straight walled case, (even the 9 mm counts) you are likely sizing it pretty much all the way to the base of the cartridge. So when you seat a bullet, it expands the case as it goes in, the resilliancy of the brass providing the frictional grip to hold the bullet in place. As 918 stated, friction is the major factor holding the bullet in place. Since the case is also sized below the seating depth, this is kind of like a crimp below the bullet, in that the bullet would need to expand the case below it if it were to be pushed in deeper. Semi-auto bullets are mostly in compression, in that the bullet is mostly pushed inward during feeding, and even being bounced around in the magazine. But because the case is fully re-sized below the bullet, it would be difficult to push it in without a major effort.

On the other hand, a crimp is much more common with revolver bullets, in that it helps prevent them from backing out. When a revolver fires, the recoil jerks the remaining cartridges back by their case rims, pulling the case away from the bullets. The crimp helps keep the bullet from backing out.

Most autoloader bullet designs do not have a crimping groove, as bullets are not prone to backing out from recoil as in a revolver. Secondly, the case headspaces on the mouth, and a crimp is probably not a good thing to headspace on.
 
Status
Not open for further replies.
Back
Top