We see the FN 5.7 do it and that's a pretty high pressure round. So why don't we see more of it?

I think it'd be great for CCW. I know we can't CCW in NJ, but for those who can it'd be cool to see a

quality polymer upper compact/sub compact that was super light. I guess the polymer revolvers

are the closest things I can think of like the LCRs. I wonder if we'll see this in more semi autos?

The FiveseveN uses a steel slide encased in a polymer shell.

That makes sense, but seems to be effective in saving weight. I wonder how much lighhhter a Glock would be built like this. Also wonder if that design works on other calibers.

I don't know if I would trust a gun at those pressures and those velocities, pushing anything over 80 grain bullets not made out of steel.

 

Competition "race guns" push those velocities in compensated guns, but in non compensated, can you say Kaboom?

 

The 5.7 is a cool round, but can we really call it a success? Over-penetration a real risk I would think in a CCW situation.

 

You do have Capacity with the 5.7, however it is kind of pointless in NJ, when we are limited to 10 round mags in a gun that was built for 20? or the PS90.

If you ever seen how a barrel "flowers" when an overpressure round lets go, you really get to appreciate that steel slide. I've seen barrels that peeled open and peeled and bulged the slide and nothing happened to the shooter. A plastic slide would have probably exploded into little shards seeking every bit of exposed eyeball on the range. No thank you. Please don't forget you are dealing with 35000 PSI, and that is a very large number.

You can probably build a gun with a polymer slide that will handle the pressure but other considerations would apply. You would need a super power recoil spring to slow the slide down on the way back. Try the slide on a blowback operated centerfire like a Hi Point which has a metal slide. If that's an 8 oz slide and need a 20 lb spring my shade tree mechanical engineering tells me you'll need a 28 to 40 lb to slow that 4 oz polymer slide down on return. If there's a real ME out there feel free to comment and correct me if needed as I don't have my reference materials with me and not sure which formula applies. In any case such a strong spring would require the frame to be beefed up substantially.

 

If you make a locked breech gun with a polymer slide similar issues will apply. Now in a design like the 1911 the sole purpose of the recoil spring is to return the slide to battery and reload the chamber. You can safely fire a 1911 without a recoil spring as it doesn't unlock until the chamber pressure drops way down. Using an extra power recoil spring so you can shoot hot loads is fooling yourself. A slighty more powerful spring may give you more positive feeding with some bullet designs like SWCs but does nothing for hot loads. A super extra power spring with a steel slide only puts extra stress on the frame as that heavy spring slams that slide forward a lot harde than the frame was designed for. Eventually you will crack the frame. However with a polymer slide you will need that extra power spring to ensure proper feeding due to the lighter weight of the slide.

 

There are some people on this forum that seem to strive to get the lightest trigger pull possible on a DA revolver which shows they don't have a full understanding of how a revolver works and think they can compensate for their poor technique with a light trigger. If they balk at dealing with a smooth 8-10 lb trigger imagine how they feel about a twice as heavy recoil spring?

 

I've never understood the fascination with super lightweight handguns. I hear people say "I don't even know its there" but if I'm carrying a gun I want to know its there. I'd rather have that 24oz 640 with less than half the free recoil of that 9 oz moon metal gun that costs twice as much. So much easier to control and shorter recovery time. I don't think I'm the only one who feels this way.

Well there is a point to light weight slides, which is why a lot of competition guns have bits milled from the slides, and running supper light springs. The slide of the gun moves ABOVE your hand, and by not being inline with the bones of your arm it creates torque which creates muzzle flip. The higher the moving mass the more muzzle flip you have. If you can lighten the slide you can reduce that.

 

I like light slides just fine, but it really don't want one made of plastic.

 

Go find that 5-7 kaboom pictures set, and indeed the steel slide frame is still there but .. none of the plastic is except for a bit at the muzzle. Where do you think that went flying to?

Well there is a point to light weight slides, which is why a lot of competition guns have bits milled from the slides, and running supper light springs. The slide of the gun moves ABOVE your hand, and by not being inline with the bones of your arm it creates torque which creates muzzle flip. The higher the moving mass the more muzzle flip you have. If you can lighten the slide you can reduce that.

 

I like light slides just fine, but it really don't want one made of plastic.

 

Go find that 5-7 kaboom pictures set, and indeed the steel slide frame is still there but .. none of the plastic is except for a bit at the muzzle. Where do you think that went flying to?

 

That's all true I was just hitting on some of the downside. In any case a lightened metal slide still weights a lot more than a polymer one would.

What's the point? lower the weight? your trying to find a solution for a problem that doesn't exhist.