How to tune 1911 magazines and magazine catches

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How to tune 1911 magazines and magazine catches

Post by Sa-tevp on 3/1/2015, 7:59 pm

After my first 200 shot run with a Ransom Rest and comparing a friend's Metalform round follower magazine with two of my Checkmate Hybrid magazines, I'd like to ask the community what characteristics of magazines and magazine catches affect accuracy. While I will admit the one 10 shot, two reload group I shot with my friend's Metalform magazine is not enough data to build on, I did think I saw that each magazine used had different grouping effect. It also appeared different shots had characteristics, such as the first shot from slide lock, the first shot after magazine change with a round in the chamber and I think the ninth round seemed to be out.

So...

How do you tune a magazine for best accuracy/performance?

And...

How do you tune a magazine catch for best accuracy/performance?
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Re: How to tune 1911 magazines and magazine catches

Post by DavidR on 3/2/2015, 10:01 am

I know many have talked about mags and accuracy, but id like to hear how it does it since the round is stripped from the mag and then enters the chamber where the slide closes behind it, the mag has long been out of play before the firing pin sets off the round. Ive ransomed thousands of rounds and you can change a group in a 100 ways, its a real art to get the feel to doing it so you repeat it the same shot after shot.
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Re: How to tune 1911 magazines and magazine catches

Post by Rob Kovach on 3/2/2015, 11:50 am

Ransom rests take much practice to master and obtain repeatable results.

There are several other threads that talk about testing for 50 yard accuracy with different magazines and different magazine springs--there is something to it, but I never remembered anyone saying there was a way to tune them.
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Re: How to tune 1911 magazines and magazine catches

Post by DavidR on 3/2/2015, 11:56 am

the tuning of mags is all about reliable feeding, not increase in accuracy that ive read
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Re: How to tune 1911 magazines and magazine catches

Post by Rob Kovach on 3/2/2015, 3:04 pm

DavidR wrote:the tuning of mags is all about reliable feeding, not increase in accuracy that ive read

I agree.

The other posts about changes in POI for 50 yard testing concluded that variations in POI had to do with pressure of the remaining rounds in the magazine emparting force on the barrel, and either the magazine tests well on the long line or it doesn't.
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Re: How to tune 1911 magazines and magazine catches

Post by Sa-tevp on 3/2/2015, 7:15 pm

Thanks for the replies. It sounds like magazines are like barrels, in that a lot of luck is involved even when one tries to engineer a good unit. Some come out missing a magic something.

Granted, for a magazine, there are a several dynamic variables involved, such as geometry, spring tension, and slide operating speed.

My first use of a Ransom Rest left me frustrated that I couldn't get better consistency with the result. I'm used to getting familiar with test equipment and my standard practice is to bench check any unit until I can get confidence in it. On the plus side I made several three inch groups with a worked over Range Officer (Thanks DavidR!) with seven or eight shot sub-groups in the 1.25 to 1.75 range. While I didn't like the fliers, it looks like the pistol/ammo will put me in the pack.

How often does the magazine catch interfere with the magazine follower in feeding?
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Re: How to tune 1911 magazines and magazine catches

Post by Jon Eulette on 3/2/2015, 7:40 pm

Magazines are tunable! Old school Colt and military mags needed adjusting for proper release of cartridge for a smooth transition into the feed ramp/chamber. Some mags will clunk a round into the chamber. Not conducive to good repeatable chambering of the cartridge. A magazine should release rim so that it slides up breech face under the extractor. If released too late the extractor will snap over the rim and is not smooth. Again we desire smooth chambering/feeding of cartridge into the chamber. Newer magazine design is much better than older magazines. I've had much better success with the newer mags obtaining smooth chambering hen I build a pistol. 
Jon
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Re: How to tune 1911 magazines and magazine catches

Post by Rob Kovach on 3/2/2015, 8:05 pm

Yes Jon, magazines are tunable for appropriate feeding--we covered that above...the OP asked if there was a way to tune the variations that make some magazines better/worse for actual point of impact at 50 yards.
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Re: How to tune 1911 magazines and magazine catches

Post by Jon Eulette on 3/2/2015, 8:08 pm

Like Jerry Keefer says, "they have to chamber smoothly"! No speed bumps LOL. Another reason the Marvel disconnecter notch/groove is so awesome; smooth!
Jon
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Re: How to tune 1911 magazines and magazine catches

Post by Rob Kovach on 3/2/2015, 8:29 pm

right....but does ANY of that effect 50 yard accuracy is the question.
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Re: How to tune 1911 magazines and magazine catches

Post by Jon Eulette on 3/2/2015, 8:53 pm

Severely! Clunking causes eratic cycling which gives poor grouping in hand or rest. Smooth cycling equals repeatable chambering and better grouping. Especially shooting from hand you can notice shot dispersion from poor cycling pistol.
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Re: How to tune 1911 magazines and magazine catches

Post by JIMPGOV on 3/3/2015, 11:06 am

Jon Eulette wrote:Like Jerry Keefer says, "they have to chamber smoothly"! No speed bumps LOL. Another reason the Marvel disconnecter notch/groove is so awesome;  smooth!
Jon
JON PLEASE EXPLAIN THE MARVEL DISCONNECTER NOTCH. TIA JIM P

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Re: How to tune 1911 magazines and magazine catches

Post by JayhawkNavy02 on 10/13/2015, 3:40 am

Is this the thread that answers your question Jon, albeit a little late.

Cheers,
Derek

https://forums.1911forum.com/showthread.php?t=283863



Last edited by JayhawkNavy02 on 10/13/2015, 9:10 am; edited 1 time in total
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Re: How to tune 1911 magazines and magazine catches

Post by Jerry Keefer on 10/13/2015, 8:59 am

A lot has come to light since that old 1911 forum thread..Once Bob began teaching the cut at MCC, we felt free to disclose the particulars, but, there have been several old S&W 52s discovered with the disconnector cut. So:suspect:....The 52 is sensitive to the cut, and much  care is required to prevent feeding issues..
The modification is so effective, I wouldn't consider having a slide witout it..
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Re: How to tune 1911 magazines and magazine catches

Post by JayhawkNavy02 on 10/13/2015, 1:35 pm

I have tremendous respect for someone who not only does incredible work, but then sets about to teach others in an effort to avoid the loss of knowledge.  Mr. Marvel is a class act.  I wish I had been early enough to have him build a pistol for me, and that applies to you too Jerry.  Thank you for what you guys do.
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