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Para Mag Tunning


PaulW

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I have a friend of mine that is shooting a Para .40 cal and his magazine lips seem to out of wack. Was wondering if anybody had any dimension that they found work for para .40 cal mags.

Thanks....

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STI has a page on their website that gives the nominal dimensions for para mag lips. For .40 this is supposed to be .385 - .395. Be careful, though, all the factory mags I have from para are tighter than this and they work fine so proceed very carefully.

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I have NO idea!

My P14 (45) mags won't feed reliably with more than 12rds in them.

The 17rd capacity mags work great in Lim-10 division. :huh:

What specific problems is he having?

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I tune mine to about .37/.38 (inside measurement between the feed lips) and they feed just fine. I have done this to both the hi-caps and the 10 rounders (actually, this is where the 10 rounder I got from Dawson was tuned to and hence, where I started from). The other Para 10 rounders I got came in anywhere from .36 to .39 and weren't very reliable at either end of that spectrum. Hence the tweaking.

Has your friend polished (or had polished for him) the feed ramp on his Para? Dawson polished mine to a mirror sheen and I have had maybe a half dozen FTF in well over 5K rounds...and I am not so sure those FTF were not my fault.

FWIW...I understand from a fairly reliable source that one can take a P14 hi-cap mag and "tune" the feed lips down and they will run just fine in a P16. No need to change the follower. Just a bit of a squeeze in the old bench vise and off you go, supposedly. They still will feed .45 too (acccording to my source). He didn't say how well they would still feed .45 though so I would use this dimension as a recommendation for the .45.

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after about 150k rounds through Paras with Para mags, I have never encountered a FTF due to feed lips off spec. In normal use, feed lips will continuously open up, eventually so far that the mag binds against the frame and won't fall free anymore (check this with just the mag body, worn followers can also make the mag not fall free). I have found feed lip dimensions in Paras an uncritical issue. Yes, they will eventually have to be bent back, but you get notice of that other than by FTF.

--Detlef

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Thanks Guys...I will pass along all the good info. Basically he has a super light slide, one of Brazo's, that is fit to a para frame. The jams he's getting are when the round gets pinned against the feed ramp. He has polished the feed ramp, check and changed the extrator, checked the extractor tension, changed mag springs, and has tried several different magazines. He has also tried different weight recoil springs and is not running a shock buff. I have not really looked at the gun, but did look at one of his mags and the feed lips were pinched together more at the front than the rear. Thus my original question.

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I agree with Detlef.

Most people but way too much emphasis on width of the feed lip dimensions. As long as the feed lips hold the ammo in the mag, the slide will push the cartridge forward. The lips should be parallel, and not wider at the front. If the front is too wide, the rim of the case will release too early and cause more of the bending, (opening up) problem that Detlef discribed.

How long the feed lip, (back to front) is more important on the Para .40cal. In most cases, factory length ammo is too short for the Para .40 because the feed lips are too short and release the rim too soon on feeding. This is why most shooters will load their ammo longer to solve the feeding problem.

If the surface condition inside the mag tube is rough, the mag will not function right. All of the late model tubes from Para are powder painted. This painted surface wears out fast, so if you have a new mag that runs now, it won't later and you will think that the spring is bad. Polish the inside of the tube were ever the follower and cartridges rub. Lubricate the inside of the mag with a silicon rag when ever you clean it.

I would not recommend using the Para .45cal mag for .40cal ammo. By the time you bend the lips in far enough to hold a .40, the cartrigde will sit too low in the frame, and the slide might have a hard time catching the back of the case to feed it. It would have the same effect as if your mag catch was worn out and allowed the whole mag to sit too low. Second, the internal dimensions of the Para .45 mag are too wide for the .40cal and will cause some binding of the cartridges and could cause a round to roll past the follower.

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feed lip width does change release point. So, indeed, too narrow feed lips could delay release to the point where these jams occur. As I said, I have never encountered *this* problem because the lips get wider with use. But I suppose too narrow lips could cause it. You would think that trying several mags should eventually bring about one that would work, it's just not very likely that all mags have this out-of-spec measure.

Beven might have a brilliant idea, but I'd continue to look for the usual culprits: mag spring, binding recoil spring, follower problem, mags not polished/tuned...

--Detlef

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Good info Detlef and Beven, thank you. So what is a good length for loading .40 cal in a para? I'm just trying to think of all avenues for him. Not sure what oal he is loading to right now.

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I'm loading to a slightly long 1.155". This runs flawlessly in four Para mags and one STI/Para mag.

I came up with this length when I showed up at a match without ammo (smart, huh?), a friend let me shoot his ammo and it worked fine. So thats what I've stayed with.

Al

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I have a Para frame/S-I Slide/Wilson non ramped barrel I just finished and it runs flawless with 19 rnd Para mag with Dawson basepads, Wolffe springs and followers. It runs flawless with 155 to 200 grn truncated cones loaded at 1.150 to 1.200. With Semi wadcutters it's a nightmare to feed though. I think I'm lucky it feeds great with the exception to just one type of bullet. Anyway, my para mags have lips spread in between-from .358 and .375. They are a little narrower at the front. My S-I mag is also about the same in spread, but it holds one less round. If I can turn back time I'd buy para mags. Too much tweaking with the S-I mags to make them run. Josh

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  • 2 weeks later...

Para 40 mags of mine measure from .356 to .390(front measurement between lips). That is smallest to widest of four mags and the cheesy little 10 round mag that has never been used is .370 for the front of the lips. I have never had a mag fail to feed. I guess that the measurement isn't that critical. If they are hanging on the feed ramp maybe it is the mag catch. The Para factory one is plastic. It will wear quickly. That can cause the mags to sit low and not feed properly. OAL is critical on Paras. I load to 1.160 or longer for proper feeding. Shorter rounds for my Glock 22 which MUST be factory spec. or shorter to feed are not reliable in my Para. TXAG B)

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  • 1 year later...

I had a mag yesterday that was causing the trigger to stick back and was hard to seat, checked dimensions with and without ammo and I could hardly see a difference between it and the good ones except that when I looked at the mag from the front I could see that the follower on this problem mag was sticking up higher than the others, I squeezed it gently in my bench vise until this follower was not sticking up any further than the rest. Checked out fit and operation and the problem seems to be solved.

Is there are better way to adjust the taper on the mags?

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