Smith & Wesson M&P 5.7??????

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Fotis
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Smith & Wesson M&P 5.7??????

Post by Fotis » 26 Jan 2023, 10:40

So I have the FN 5.7 x 28. A while back I had no experience loading with it. I ran a Q/L for it. Spoiler alert it does not work!
Anyway simulation said xx grains of Lilgun would push a 40 gr V-max to 2K fps! Long story short I tried it and the neck separated and stayed in the chamber! In the FN I got neck separation because the case is not sealing and staying in the chamber long enough due to blowback design.

Would the new gas operated smith with the locking/rotating barrel be better suited to slower powders for better performance due to the delay in unlocking?
A good analogy would be the 10/22 mag being chambered for the 17 HMR---did not work out because the action opened before the power charge of LIL gun was completely burned. Savage solved this with the Savage A-17 with the delayed action opening patent.

Am I correct in my thinking or off completely?

Toprudder
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Re: Smith & Wesson M&P 5.7??????

Post by Toprudder » 27 Jan 2023, 10:17

In my mind, the locked breech design would work.

Fotis
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Re: Smith & Wesson M&P 5.7??????

Post by Fotis » 27 Jan 2023, 13:23

So you think I am thinking it out correctly?

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panzermk2
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Re: Smith & Wesson M&P 5.7??????

Post by panzermk2 » 30 Jan 2023, 09:54

locked breach will not work with 5.7.


There other in depth conversations in the re loading area about QL just not working for the 5.7

Delayed gas SHOULD be perfect for the 5.7 IF S&W has made a quality fire arm.
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Grantness
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Re: Smith & Wesson M&P 5.7??????

Post by Grantness » 30 Jan 2023, 14:45

Let’s assume it can accommodate hotter loads / new powders… now you have to worry about keeping your ammo separated.

Fotis
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Re: Smith & Wesson M&P 5.7??????

Post by Fotis » 30 Jan 2023, 15:55

Grantness wrote:
30 Jan 2023, 14:45
Let’s assume it can accommodate hotter loads / new powders… now you have to worry about keeping your ammo separated.
I'd sell the fn

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Re: Smith & Wesson M&P 5.7??????

Post by panzermk2 » 31 Jan 2023, 09:58

Meh honestly the FsN can handle loads well into primer popping, neck separating 65k,. I really would not worry about it.

While the S&W uses delayed gas blow back they are also using a rotating barrel with lugs. This system mirrors the lug design used in the Sig Arms Mauser M2 pistol.

This area has me the most concerned. If the S&W pistols fails it will be with the barrel lugs. The lug system is inherently heavier than any other system. It adds a great deal of complication to make work in a small carry pistol. Complicated metallurgy also. I really question S&Ws ability to keep the tight specifications needed, metallurgy needed and at the current price point. I suspect we will see reports of barrel lugs shearing or slides cracking along the races the lugs run in.
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Re: Smith & Wesson M&P 5.7??????

Post by Papaorca » 09 Mar 2024, 01:38

The Smith $ Wesson M&P 5.7 is my latest acquisition. I really enjoy shooting it, to the detriment of my pocket book. I have encountered an unexpected problem. I had the temerity to shoot it suppressed.
My son and I were shooting, everything was working well, groups were reasonable (considering who was shooting them) and we decided to mount a Dead Air suppressor on it.

What a difference! Bullets were all over the target and the holes they made were no longer nice and round! They were literally going through the target sideways!! (This has not happened with any other gun that has had this suppressor mounted on it.) After five or so rounds we stopped using the suppressor and everything returned to normal. We were experiencing "clipping" or "baffle strikes". The barrel is enclosed in a shroud. Instead of threading the barrel for a suppressor S & W threaded the shroud, which creates an alignment problem. Smith & Wesson knows about the problem but does not yet have a solution.

I called them after sending an email and waiting several weeks for a response. The company line now is "The gun hasn't been on the market long enough to test it and compile a list of compatible suppressors." When I mentioned the in-house suppressor made by S&W the answer was the same.

My purpose for bringing this up is not to trash S&W as much as to let folks know that there is a problem with this gun and shooting it with a suppressor. S&W has created quite a problem for themselves and it will be interesting to see how they will address it or even if there is a solution.

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Re: Smith & Wesson M&P 5.7??????

Post by Buffman » 09 Mar 2024, 19:41

Yep I documented this when i first got it. Let me ask your, Your DAM, is it threading all the way to the barrel's shoulder or are their exposed threads left?

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Re: Smith & Wesson M&P 5.7??????

Post by Papaorca » 17 Mar 2024, 18:24

There are no exposed threads. I tried a 0.25" threaded spacer at the bottom with the thread protector sitting on top but that didn't help either.
I will give it some time (yet to determine how much) and I will be back in touch with S&W for a progress report.

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