Stampings!

[Handy]

I was just looking at my top five firearms (at the moment). 3 pistols: HK P7M8 and P9S and a Sig 225. Rifles: HK91 and Robinson M96. The common thread; extensive use of stampings.

And I mean extensive. This isn't just pansy internal parts for stampings, like a Glock. All three pistols have stamped slides, both rifles have stamped, welded receivers. All are tough and super precise is construction.

All of which makes me wonder, why is "stamping" such a dirty word? Yeah, its not hammer forged machine billet, but it's tough, hard, perfectly dimensioned and STEEL!

I would contrast this process with injection molded plastic (we like the grown-up word "polymer") and cast aluminum. All three processes are less expensive, but in the end a stamping is still resilliant, strong steel. And for many thin parts, its probably the strongest way of making a steel piece.

I guess I would much rather have a stamped sear than an MIM one or a stamped and welded frame than an alloy one. I'm certain those stamped steel parts will outlast the competing cheap material alternatives.

 

[ether]

I'd take a good stamping over a casting any day.

BTW I didn't even realize the P7 had a stamped slide. I haven't handled one in years, but I have one on the way so I'll see soon enough

 

[BigG]

Stamping is legit so long as the material is of good quality, imho.

 

[9mmepiphany]

i didn't realize that my p7 had a stamped slide either...just never thought about it...now i'll have to check when i get home.

i actually prefer the stamped slide sigs to the domestic stainless ones...i like the shape and serration pattern

 

[Blackhawk]

9mmepiphany, there's a lot of difference between a stamped metal part and a forged one. Are you sure your P7 doesn't have a forged slide?

 

[9mmepiphany]

up until handy posted that the p7 was composed of stampings and ether mentioned the stamped slide, the thought had never crossed my mind.

i knew about the hk's and sigs, but i still think my p7 has a forged slide. the only thing that would even cause me to think otherwise is that the breachblock is welded into the slide

now the p9s had a true stamped slide with the slide being retained to the receiver by punched indentions

 

[lunde]

All HK P7s have forged steel slides, but they are composed of two pieces that are welded together. Only some of the inner workings, specifically attached to the frame, are made of stamped steel. The breechblock is the separate part that is welded in place, and where it meets the end of the slide at the rear is filled and smoothed.

 

[Handy]

Pardon if I'm wrong, I was told that the slide was stamped into that shape, then muzzle and breach block welded in.

 

[lunde]

I own seven HK P7s, and I know from inspecting their innards that the slides are made exactly as I described.

 

[Blackhawk]

Seven P7s! A collection of collectibles!

 

[Handy]

I've only had two, but I wasn't saying that I thought you were wrong. This is something I read somewhere and seemed credible given the need to weld in the breachblock. I'll buy that it's a machined forging.

 

[9mmepiphany]

i went home and checked both of mine last night...it is forged

i'm also thankful that lunde chimed in...his collection of p7's are beautiful (ayup, i belong to the cult too)

handy - in forging, the slide is stamped...they pound the metal into the desired shape.

common usage or the term "stampings" refers to the phrase/term "folded and stamped (slide)", which i remember first used in conjuction with the hk P9S and G3 (hk-91). the slide is formed from a flat sheet of metal which is folded and pressed into the desired shape. the hk's are a classic example with there "thin" receivers (G3), the "sheet" of sigs is much thicker...with formed rails in the slide.

 

[ether]

I finally got my P7M8 today (yeehaw!) and the slide is definitely machined.....probably from bar stock. It is an extremely well-made pistol. The squeeze-cocker and mag release are obviously stamped.

 

[Handy]

I was just looking closely at my slide. The main body of the slide is no more than about 1/8". While the breach block is obviously welded in, so is the back plate. The welds have been machined away, but there is a finish difference and small flow marks where the two pieces merge. I could not find similar marks on the muzzle end. The inside void of the slide is very smooth and does not appear to have been created by machining.

I do not know what the official difference between forging and stamping is, perhaps thickness of working material? But here is how I think they made the slide:

1. A 2" wide by 1/8" piece of metal is roto hammer forged or stamped into the basic profile of the slide around a mandrel. (HK uses this process for barrels.)
2. The muzzle end of the slide is likely formed during this process and the mandrel withdrawn to the rear.
3. Slide rails, ejection port, cocking serations, dovetails and the like are machined. Most of the slide does not require any machining and comes from the forge in the correct shape and finish.
4. The rear plate is welded and finish machined.
5. The breach block and pieces that hold in the striker assembly are pressed in and welded with two 3/4" welds.
6. Slide is blued. Mine is turning plum, and is most notably that color on the steel from steps 1. and 2. The back plate is noticeably blacker.

I imagine that the plum color comes from a steel alloy and density that doesn't take to blueing as well as the metal in the rest of the gun. There is actually much less metal there than in any other pistol slide I can think of, and a special process to produce an uncommonly strong slide was used (since the blowback forces have less volume of metal to act over).

So why are the back plate and breach block seperate welded pieces? It may have been a simpler way to achieve the the camming area for the striker. But I would not be surprised if the breach block welds were a late design change; and the block was originally designed to by pressed and/or pinned in place, like the P9S and Sig 220.

 

[Handy]

Lunde,

I was looking at my stamped P225 slide (I only have one) and noticed that it is exactly the same thickness as the P7 slide material.

When looking at your (seven) P7s, how were you able to determine that the slide was forged, not stamped?

Or are "stamped" Sigs not stamped either?