Anyone thinned a slide yet?

Discussion in 'The Bull Dawgs Club' started by squirrel_slayer, Dec 14, 2018.

  1. squirrel_slayer

    squirrel_slayer

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    So this forum is becoming hazardous to my wallet. The one thing that has always detracted me from the GAP's was the fat slide. A good friend of mine has a 30s and as many have observed if they can do it with acp then why not GAP?

    I think i've read somewhere that the g4 37 has the nominal width slide like the 9's, 40's?

    Seems I missed the boat on SG's $269 G37 trade ins so i'll be keeping an eye out for a deal like that after the new year (4 kids and Christmas=no gun funds lol)

    I have access to a bridgeport and I'm thinking there shouldn't be much worry about thinning the slide .060" a side so it will fit my holsters I currently own and maintain the feel i'm used to (and ditch the extended slide release)

    Just figured i'd ask if anyone has done it. If not I may be the test dummy pending finding a cheap trade in.
     
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  2. Taroman

    Taroman US Army Retired

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    Not a machinist or metallurgist, but IMHO, it should work just fine.
    IIRC the heavy slide specs originated with the 20/29, and, for ease of production, carried over to the 21/30.
    As you said, the lighter geometry runs just fine in the 36.
    So, fire up that Bridgeport and have at it.
    Keep us posted..
     
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  3. heavyduty

    heavyduty

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    I very briefly owned a LW thinline GAP upper, but I never even shot it - it was an impulse purchase, and I decided I really didn’t need another caliber in the cabinet. Last I heard the GT member that I sold it to was having fun with it.

    Off topic for this thread, but I’ve always wanted a 21 with a 30s thickness slide. If you try this, please report back!
     
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  4. Gokyo

    Gokyo

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    Isn’t the 41 kind of a thin slide Glock 21 with a slightly longer barrel?
     
  5. squirrel_slayer

    squirrel_slayer

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    Correct. One minor detail I forgot about was that the 30s and 41 both had slightly thinned out barrels (wondering if they left material on the inside of the slide to keep weight up.

    I know it's thinned enough that it's not recommended to run 45 super loads from them where as the others will handle it fine with the addition of a beefier recoil spring and even the 460 Rowland with barrel upgrade.
     
  6. es 350

    es 350

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    https://www.google.com/url?sa=t&sou...FjAAegQIBBAB&usg=AOvVaw3KrlsjvlS88i0PBoSgod0s

    Here is a post of some Glock slide weights .

    If you do mill a slide .... have some good carbide tooling. I milled a G22 slide for a Vortex dot sight couple years ago. H.S.S. tooling wouldn't scratch it .

    The heavy slides on the GAP is what makes the recoil/ platform enjoyable to shoot IMO. Lighter slide would make it snappier to shoot... if this is not a factor then.....
    I like to experiment more than most so have at it and let us know how it works out.

    My Glock 39 slide weighs 14.5 oz with GNS

    G37 slide weighs 16.7 oz with polymer sights.

    On the subject of shooting 45 Super from G30's, G36 and G41.... it can be done , although easier on frame of gun with a few mods.
    I shoot 45 Super+ loads from all of my Glocks including G36 with some mods to make it easier on frame .

    Data from Ballistics by the inch for 45 Super list G36 as one of the guns tested for velocity with the various 45 Super loads .
     
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  7. squirrel_slayer

    squirrel_slayer

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    ES 350 thanks for the weights and pointers. I bet that tennifer is a bear to break through. Once I obtain a G37 i'll definitely take it for a test drive before modifying it. I bet that 39 is a riot! never seen one in the wild. has to be pretty intimidating tiny pistol with a giant bore! :supergrin:
    Would be interesting if you could squeeze a shortened 50GI case in small frame and make yourself a 50 GAP :devildance:
     
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  8. squirrel_slayer

    squirrel_slayer

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    So :devilish:ES 350......whats your take on a 38 casull in a G37 :drunk:
     
    Last edited: Dec 18, 2018
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  9. GRR

    GRR

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    I think it would be easier to do what LWD did and modify a G23 slide (or a G22 if you're going for full size). I think it basically widening the breach face and enlarging the hole in the end of the slide to take a 45gap barrel.
     
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  10. DLL9mm

    DLL9mm

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    I like the wide slides on the GAP pistols. It sets them apart from other models.
     
  11. es 350

    es 350

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    The 39 ..... is a great little gun!
    The addition of pierce +2 on mags make 8+1 possible.
    39's (mine anyways ) are very accurate.
    Recoil is not bad at all , as can be seen in my post above 39 slide is only 1 oz lighter than a G30 . G30 is known for being a soft shooting 45 ACP.

    With a custom slide a 50 GAP could be interesting........

    The 38/45 or 38 Casull would not work in mags or slide/barrel of a GAP handgun as GAP uses 9mm/40 frames, shorter (9mm/40 length) cut in slide for barrel block.
    But a wildcat could be made to work in GAP.... a 45 ACP case cut to 40 S&W length then necked to .35 cal. Would still be a step up in performance from 357 sig.....

    If the wildcat road is taken I would want the heavier slide to help control slide speed.

    I have threaded barrels for all my GAP's to shoot almost Rowland level loads for hunting..... the GAP (modified ACP brass)
    With 24 lb RSA and muzzle brake can achieve following performance and with less powder than Rowland or 45 SUPER.

    230 @ 1225 fps
    200 @1300 fps
    185 @ 1425 fps

    I used 200 gr XTP at 1300 fps this year to hunt deer, worked very well as did the ones I used the 230 XTP @ 1225 on couple years ago... all have been DRT.
    IIRC this year was longest shot with the GAP... Ranged 64 yds.

    Above loads from G37 has considerably less slide speed and recoil (less powder) than comparable load in G21 45 SUPER.

    Even my hunting loads [email protected] 1300 fps will not cycle if limp wristed , like when ... hunting shooting off hand .... this with 24 lb RSA and a 4 baffle brake I designed for 45 SUPER.
    Really need to make a smaller brake for SUPER GAP.

    Using less powder is the reason 45 GAP factory loads/guns shoot softer than comparable ACP chambered guns shooting same bullets at same speed.
    G37 and G21 have same weight slide .
     
    Last edited: Dec 20, 2018
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  12. squirrel_slayer

    squirrel_slayer

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    ES 350 thanks again for the great information. I don't have a case oal for the 38 casull but I've read that the 38/45 is in the .898" realm so I figured with as long as the neck is on the casull and 38/45 trimming the neck down .040"(.357 sig is .865") and chambering slightly deeper like your buddy did with his 38 weatherby would yield a gap friendly case.

    starting from 400 corbon brass would be the simple solution but it seems the other guy is using cheap small pistol primed acp brass with good results. (granted rims would need to be turned and possibly the extractor cutout?)

    If I do jump in on the GAP i'd likely leave the slide full weight as that read on the 38 wby really got me pumped! lol I'd almost be half way tempted to take it a hair lower to ".32 cal" and make a micro 7.5 bruno type loads lol

    I was going to put my first gun funds of the new year towards another stamp but you guys have really peaked my interest with the GAP and it's capabilities. The idea of a true .357 mag power level from an auto with 10+1 capacity sounds pretty awesome. Heck those Super GAP loads sound pretty sweet also.

    So i've seen that the Rowlands have mentioned the brakes are a must and it's got me wondering whats really going on there. Is the gas force of the brake pushing the barrel downwards keeping it locked longer as it's counter acting the fulcrum motion mechanically with thrust what allows these things to be hot rodded as much as they are? seem's like a brilliantly simple notion.
     
  13. es 350

    es 350

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    While powerful loads can be shot from a properly modified GAP.... a G21 or 30 is a better platform to build on.

    Threaded GAP barrels are a thing of the past since LWD stopped importing them and as far as I know the stock they had is gone.
    Along with this , the LWD barrels also have an unsupported chamber . This makes pushing the power envelope a touchy situation if not an expierienced handloader AND using the proper components.
    Not to say you or anyone else cannot do this just making you aware of it !

    As you also mentioned modifying brass from ACP to ANYTHING used in a GAP CHAMBERED platform requires at least one extra step , turning rim for gap breach face.

    A muzzle brake/compensator
    Does a couple of things.

    In competition shooting , commonly referred to as a compensator, it is used to reduce muzzle rise and recoil to make the gun shoot "flat" as possible . This allows faster follow up shots as the sights stay closer to aimpoint.
    This is accomplished by the gas behind bullet pushing on baffles of brake/comp.
    This action of gas pushes forward on brake/ barrel keeping barrel in lockup for a longer period of time. If ports direct majority of gas out the top (most do) this also helps delay unlocking of barrel by resisting the barrel lift needed to unlock lugs.
    The jet effect pushes the muzzle down, this is what competition shooter are after. Hot loads in semi auto handgun benefit from this as well in the reduction of muzzle flip. Some of the loads I have shot would be REAL wrist breakers without a brake and not fun to shoot at all!

    A brake design that catches and redirects the most gas works best. This is why a bigger (to a degree) brake is more effective than a smaller one.

    I machined a brake for a 300 win mag rifle, my brake reduced felt recoil by half of what the factory brake did and lowered poi by 6 inches! At 100 yds, a testement to how much muzzle rise was reduced. Rifle also went from 1.5"+ 3 shot groups to a .5 " rifle just by threading on a new brake.
     
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  14. squirrel_slayer

    squirrel_slayer

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    I intend to try and make my own barrel. I have a friend who owns a mill and I own a mid sized benchtop lathe (8x14) I have an old 30-06 barrel that I plan to do a 7.92x24 vbr from (30 carbine cut short) for my 17. If I get the lockwork and all done well on that then I wouldn't be afraid to try the 38/45 gap
     
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  15. es 350

    es 350

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  16. Buckeye63

    Buckeye63

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    I still have it ... Really hadn't done alot with it lately ...
    image.jpeg

    There is a fellow local wanting to swap me a As NIB S&W 638 for the slide and my extra mags ...we supposed to meet and talk about it aftr the holidays. I sorta hate to trade it off . .. Being its a unicorn...
     
    Last edited: Dec 23, 2018
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  17. fasteddie565

    fasteddie565 Combat Diver

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    Am I reading this wrong or is all of this metal removal for holster compatibility? I am all for any 45 GAP innovation, but if you have a holster made for a GAP pistol, your 9mm's will work fine in them. Call Tom at 2Aholster.com The gun retains off of the trigger guard and the slight variance in the slide width makes no difference or can be accounted for with the tension screw.
     
  18. engineer151515

    engineer151515

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    Glock originally tried the G17 slide on the G37.
    Original marketing photos showed the thin slide and noted the anticipation of using G17 holsters.

    My understanding was that the thinner slide (less mass) created timing issues that necessitated a double slide spring design.
    Ultimately, Glock went with the larger slide and the single spring design.

    My understanding - going back to 2003.
     
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  19. squirrel_slayer

    squirrel_slayer

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    interesting and it does make sense.
     
  20. Firecop203

    Firecop203

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    More than my wallet could afford. My 37 fits just fine in my 21 holster.