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.45 extraction issues

Posted: Mon Oct 28, 2013 7:49 pm
by RandomShotz
I have a S&W 945 that has had chronic extraction problems. I bought it used, fiddled and fussed with it for a while and then sent it back to S&W to see what they could do. The replaced the extractor, which was a great improvement, but there are still occasional failures to extract. I did some tests with primerless dummy rounds that I made up which are dimensionally identical to the rounds I shoot. The bullet is a 148 gn SWC from Qualitycastbullets.com which is a long-nose LSW "similar to H&G #68" loaded in Starline brass to ~1.250 OAL which puts the shoulder of the bullet just ahead of the case mouth. It is difficult to measure the crimp, but it looks to be about .461; the loaded case diameter is .470. (The live rounds have 4.2 gn BE, but I didn't want to use them while jacking around with the gun in the kitchen - the noise might upset my dog if something went wrong.)

I marked up a cartridge with a Sharpie, loaded a dummy round in the chamber and put the marked cartridge in the magazine. I then put the magazine in the gun, pulled the slide back and locked it, removed the magazine and examined the marking. Every time, a scrape through the marking showed that the rim of the cartridge being extracted struck the shoulder of the bullet and rode over the rim of the case. The gun had 8 magazines with it when I bought it and every one showed the same pattern.

Is there something wrong with the magazine lips? Should I try to mash them down a bit so that the nose of the round in the magazine is slightly lower, or is something else going on?

Roger

Extractor

Posted: Tue Oct 29, 2013 3:47 pm
by dschrank
Edit

Posted: Tue Oct 29, 2013 5:12 pm
by RandomShotz
What you say about the extractor is true about straight blow-back pistols, like the .380, .22 and other low-power cartridges. Most .45's have a delayed action and the recoil energy moves the slide and barrel backwards together until the barrel is pulled down and out of engagement with the slide. My understanding is that by the time that happens, there is no pressure in the chamber to blow back the empty case and it must be drawn back by the extractor. However, I am not a gunsmith and would not be surprised if I am wrong about that. The extractor pivot pin is too tight for me to experiment with it especially considering that I have proven more than once that I should not be allowed to operate a pin punch in the vicinity of a firearm.

What my pistol is doing is sometimes leaving the empty case in place and returning to battery and sometimes pulling the case out until it stops against the mouth of the next round and hanging up there. I was using much less crimp for a while and in some cases the extractor would take a chip out of the case rim suggesting that the extractor had a good grip but the extraction was stopped by interference from the next round in the magazine. Increasing the crimp allows the extracted case to ride over it more easily but there are still occasional hangups.

You mentioned a line on the follower as well as on the cartridge - I expect there to be a line on the mag follower since the last round is dragged across it as it is stripped. Just to be clear, I put a dummy round in the chamber and returned the slide to battery before putting the magazine with the marked cartridge in the gun. Any scratches on that cartridge would be from the case being extracted and not from the previous round being stripped off. Also, as I am manually pulling the slide back I can feel a bump in the motion when the extracted cartridge strikes the next round.

Of course, this may all be normal and I am just noticing things because I am paying attention to them for the first time.

You are right about the load - it is light. I was told to start with 4.1 gr BE and work up to 4.6 gr max and I thought I'd take it easy since I am only shooting at 25 yd. I'll try 4.4 gr and see where it gets me.

Roger

Posted: Tue Oct 29, 2013 7:51 pm
by Expendable
Roger,

I've heard of this problem when trying to shoot SWC's through some Glock 45's.
The consensus was that on some Glocks the relationship (vertically) between the chamber and the top of the magazine caused the extracted round to hook the edge of the SWC bullet on the way out of the chamber and cause the condition you have.
There was no real fix except to shoot round nose bullets instead of SWC's.

Kurt

Posted: Tue Oct 29, 2013 8:53 pm
by RandomShotz
Kurt -

I hope that's not it - the SWC's make such nice holes, even if they're not always where I want them. More importantly, I have 750-800 of them left. If the heavier load does not work, I may try to modify one of the mags to see if that does. The worst that could happen is that I end up with only 7 functioning magazines.

But if I were to go to LRN, is the 230 gr the slug of choice? I've been buying bullets from http://www.qualitycastbullets.com/bullets - they're cheap and readily available and I haven't had the leading problems that I've had with other bullets in this gun or my S&W Model 52.

Roger

Posted: Wed Oct 30, 2013 7:20 am
by Expendable
A heavier load may help by speeding up the slide movement and getting the spent case past the top round in the magazine before it can move up, but I'm not sure.
I would imagine the 230gr would be ok, some casters make a 200gr round nose or even the 185 button nose may help.

Kurt

Posted: Wed Oct 30, 2013 9:35 am
by Kirmdog
What type of lips are on the magazines you have now?

If they are GI lips that might be your problem because they tend to leave the cartridge in the magazine ride a bit high. If they are doing that then the next cartridge in the magazine would be riding high and when fired the case being extracted could catch it's rim on the next rounds shoulder of the SWC pulling the extractor over the rim of the fired round. When firing RN you would never notice this but with the sharp edge of the SWC sticking up to high it could cause the problem.

I would give either hybred or WC lips a try and see what happens.

Just a thought.

FWIW I have used 4.2 of BE with the 185 and have no problems. Increasing a powder charge to clear a mechanical problem is always a bad idea. I have even used 3.6 with the 185 grain bullet and had it function fine but got better accuracy with the 4.2 load.

3.6 of BE with a 200 grain SWC is my go to load and has never cause a problem with FTE when the proper recoil springs are used
Kirmdog

Posted: Thu Oct 31, 2013 7:34 pm
by RandomShotz
Kirmdog -

When S&W decided to make the 945, they decided to make it as much not like the 1911 as possible. The first time I picked it up it fit my hand unlike stock 1911's, which is why I bought it. (That, and poor impulse control.) However, there are no other aftermarket options for it - the mag does not even fit any other S&W's. So it's bash the lips myself or try something else.

This weekend, I may take a mag in to the shop and see if I can do any good. I will also be shopping around for some other bullet that is affordable, available and has a rounder profile. Knowing that the mag is probably holding the rounds that way by design (i.e., it's not a bug, it's a feature) makes the idea of just loading hotter somewhat less attractive.

Thanks a lot for all the ideas - I appreciate the time you guys took to try to help me with this.

Roger

Posted: Mon Nov 04, 2013 8:24 am
by Kirmdog
RandomShotz,

Thanks for pointing out the magazine difference with the S&W. I did not know this, nobody in my shooting club has one. Thanks for the education, I'll store this in my hair covered computer. Good luck with finding a cure to your problem and let us know if and when you do find it. It will be interesting to hear what it might be.

Kirmdog

Posted: Mon Nov 11, 2013 9:22 am
by RandomShotz
I tried modifying one of the magazines with mixed success. The lips are very hard and only moved a little bit with some fairly forceful smacking. In the process, the magazine closed up a little near the top and this interferes with the follower activating the slide stop. There is still a bit of a hangup on the bullet's shoulder and ejection is weak. I will probably continue to bash it this way and that just to see if I can make it work with the LSWC bullets so I can use up my stock.

However, I also ordered some round nose flat point 200 gr bullets from Missouri Bullet, loaded them over 4.2 gr BE and they seem to work very well. The gun functions perfectly and ejection is lively and consistent which is important since I use a net brass catcher. I don't have any way of objectively testing accuracy, but at 25 yd they put the onus for accuracy squarely on me and I bought a bunch more. It looks like the problem is solved. The Missouri bullets are so nice that I even bought a batch of 148 gr .38 special DEWC to see how they work in my Model 52.

Thanks again, guys!

Roger