Guncrafter .50GI Glock 20/21 Conversion Kit

[Sharps40]

Figgered I'd start a separate review. Will get to the range tomorrow. Hopefully some video from that but for now, the GCI .50 GI Glock conversion arrived with 60 rounds of fresh ammo.

My initial impressions are good and the gun assembles quick and easy, simply put on the barrel/slide assembly, insert a loaded mag of .50 GI and drop the slide. Ready to go. Dry, the new upper assembly passes all function checks. Range tomorrow.

The package...

The Ammo....(reload data for bullets 180 to about 350g weight is provided with the gun. Brass/dies available from GCI.

The oft vaunted 45 ACP, a personal favorite and this one is my carry load of 230g Federal Hydrashok, flanked by a pair of 50 GI rounds capped with 275g hollow points.

Inside the box, a slide/barrel assembly with steel guide rod and spring and a 50GI magazine with extension to hold 9 rounds in the mag.

Stainless slide. Like the Glock slide, not a single machine mark on it. Both Glock and GCI finish work is exquisite.

Inside the slide, all seems to be perfection.

Three of the four components needed to convert a Glock 20/21 to .50 GI.

Inside the barrel, conventional button rifling. Good for jacketed or lead bullets. I suspect I'll be trying the 255g or heavier lead bullets soon. Wad cutters will be wonderful for hunting.

For the time being, the platform will be this every day normal Glock 21 Gen 2.5 45 ACP. Should I like the 50 GI well enough, I may well purchase a dedicated frame for it later next year.

 

[Sharps40]

50GI mag on the left, Glock 45 ACP mag on the right. Dimpled lips on the 50 GI mag are to ensure nose of ammo is presented properly to the barrel. Each round coming up the mag will assume a base forward position on the lips, ready to feed straight into the chamber.

50 GI Slide left, slightly larger and heavier than the Glock 21 slide right. Barrel of the 50 GI is slightly larger in diameter (.650" vice .629" for the 45 ACP Barrel) but the wall thickness is slightly less on the 50 GI at .074" vice .089" for the 45 ACP barrel.

Loaded chamber indicator on the extractor can be felt when the gun has a round in the pipe.

The new upper, though slightly thicker, fits the glock 21 holster without a problem....no new leather to buy.

All together. Now the extended base plate is a bit goofy looking but it gives 9 in the mag. Though I believe I'll replace it with a standard glock floor plate sacrificing one round of capacity for better looks and less bulk.

That's it. Too bad its dark or I'd be shooting it already!

 

[Sharps40]

A fun trip to the range. 40 rounds of 275g JHP 50s fired. 39 cases recovered. I made up the difference by picking up about a 100000 once fired 45 ACP cases.

So. Recoil. Not bad. Like a 10mm in a full size or a 40 or 45 +P in a compact or subcompact handgun. But, more controllable and less hand slap than the subcompacts give your hand. Recoil, I think is best described as very slightly sharp with a touch more rise and torque than the 45 ACP +P but still controllable and easy to make hits with. As seen in the video, it hits steel quite a bit harder than the 230g 45 ACP. So. I'd have to say, the 50 GI is no Powder Puff.

My initial impression is of a keeper, likely deserving a dedicated gen 2 or 3 three pin frame.

The standard glock sights on it are useable but aweful hard to use compared to many after market options. They will get swapped out later after more practice and getting set up to reload this caliber.

I got one pinch of the little finger between grip and magazine extension. It was not to sharp a pinch and didn't raise a blister. After checking my grip, no more problems like that.

I am reasonably sure I will replace the extended floor plates with standard glock floor plates. 8 rounds is plenty and it saves about 1.25" length in the grip.

Brass flies well clear to the 5 oclock position rising high enough to smack the overhead (8 or so feet up) before bouncing down on the concrete.

Here are the videos.

Starting with 45 ACP on steel as a reference. This is standard 230g FMJ ammo at the normal 825ish FPS. I've always thought the 45 hit plenty hard. The video shows it to be true. In the second video, it appears the 50 GI hits even harder.

And here, the 50 GI on the same steel swingers.

Then I went to the dueling post and missed a couple of the resetting plates too....

Then because its so much fun, I went back to the swingers and the dueling post.

 

[Sharps40]

After a half day with Thumper on the hip....carries almost like the 45 ACP configuration....as expected. But one significant exception. That dayum magazine extension.

Its longly ugly, does nothing for my grip since the frame is big enough as is, it sticks out so far that it prints badly and makes it uncomfortable to sit in the truck.

The 45 ACP mags with flat floor plate do not roll the gun forward and into my side like the fifty's mag extension does.

So, that cinches it. I need to locate a Glock 20/21 factory flat floor plate and swap it out on the fifty mag. I'll loose one round of capacity. But, I'm used to carrying 5 in a wheel gun and it should make the 50 conversion carry the same as the factory 45 ACP set up.

I think when I call GI for more magazines, I'll see if they'll scrap the extended floor plates and just send me mags with flat ones right off the bat.

Spare mag, dies and brass arrived this week. We got bullets!!!!!. Now to find some Unique.....

 

[acmech]

Man that's awesome!

 

[Sharps40]

Some experimenting and loading this morning. Bullseye powder on hand and looking at the factory load data and some on the web, decided to start out with a load of 6g Bullseye with the 255g LSWC.

Went down to the workshop....it functions as my 12'x24' silencer. (Yer shot sounds like its a long way off, keeps the neighbors from coming unglued with unwarranted nervous nellyness). Open the window, big big oak about 5 feet from the window. Put on ear muffs, breath, aim, squeeze and the first ever I loaded it myownself 50 cal handgun SWC bullet went out the winder and into the trunk.

Gave the case a check. Slightly smaller expanded dimensions at near the base than the factory loaded ammo before firing. Primer looks good. Got some hood dents on the case mouth so, its probable a bit on the light side for the spring rate.

Loaded up 40 more for the range to function test and will have to get a 9v battery for the chronograph.

Meantime went outside with a probe and found the bullet just about 5 inches in to the live hardwood of the official backstop tree. Not bad. I'm aiming for 900ish FPS with the 255s. If doable, should provide 500ish lbs KE and plenty TKO or Momentum or however ya want to measure it. I figure at that, it'll knock stuffing outta deer and hogs during hunting season.

The first handloads.....

The backstop....

 

[Sharps40]

Email to Guncrafter and RimRock.....both have been good about responding to questions on their products.

Gentlemen,

I recently inquired on load data for the 50GI using the RimRock 255g LSWC and Bullseye/Unique powder. You were able to start me out with 6g unique. Haven't tried it yet. Have yet to find Unique locally. But, have a stock of Bullseye and as promised, my initial results. (Goal, if possible, is 950 FPS with the 255g RimRock LSWC).

The load Data:

.50 GI Case, once fired from the factory 275g loading.

255g Rim Rock LSWC

6.0g Alliant Bullseye Powder

CCI Large Pistol Primer (No issues with ignition using this hard primer)

Cartridge Overall Length, 1.216"

Crimp diameter at mouth of case, .524" (lee die as provided in the set, crimped separately from seating)

Case diameter ahead of solid web after firing ranges from .530" to .532" with the vast majority at .530". (10 fired cases checked) Primer condition, rounded edges, firing pin indent not smeared. (Photo attached).

Accuracy was just fine. Feeding, firing and extraction of 40 rounds was perfect in the Glock 21 conversion package.

Chronograph data, set one, 5 shots from 8 feet:

1. 891.1 fps

2. 872.4 fps

3. 896.9 fps

4. 886.8 fps

5. 901.4 fps

Ave: 889.7 fps

Hi: 901.4 fps

Low: 872.4 fps

ES: 29 fps

SD: 11.2 fps

AD: 8.1 fps.


Chronograph data, set two, 5 shots from 8 feet: (Shot 1 thrown out of calculations....reading was 971 fps and the chrono screens were shacking badly, I assume breeze/other interference and deleted this first shot as erroneous.)

1. 885.1 fps

2. 901.7 fps

3. 896.4 fps

4. 896.7 fps

Ave: 895.0 fps

Hi: 901.7 fps

Low: 885.1 fps

ES: 16.6 fps

SD: 7.0 fps

AD: 4.9 fps


Any thoughts? 955 fps with this bullet achievable with Bullseye powder? (I noted some "internet" data, showing upwards of 7g Bullseye with a 275g jacketed bullet at about 930 FPS. However, there appears to be no reliable pedigree for the data.....just somebodies "Chart" of loads.)

Thanks.

 

[Sharps40]

Received a return email from the Owner of Guncrafter. We discussed BE and the 255g RimRock bullet. Looking over the results and determined how to proceed and when it might be appropriate to switch from BE to Unique.

For the nonce, I'll check a round each at 6.2g and 6.4g BE, primarily for case expansion and primer condition. If things look like they can go forward/upward, I'll load a string for over the chronograph and on the paper.

If it can't go higher, I'm looking at a good general use load already that provides a power factor of nearly 229.....an easy 18% increase over the tried and true 45 ACP 230g ball power factor of about 189. If the 45 ACP can swat deer close, and its been done, this easy handling 50 should do a bit better and deader.

 

[Sharps40]

Worked up to 6.4g BE today using the no permit required silencer building and the natures own green backstop oak to fire a couple test loads for measurement. Its time to load up a string and head to the range this weekend for some chronograph work, visuals and measurements.

The test load was as follows:

.50 GI Case.

255g Rim Rock LSWC

6.4g Alliant Bullseye Powder

CCI Large Pistol Primer

Cartridge Overall Length, 1.212"

Crimp diameter at mouth of case, .524"

Case body diameter after firing measures .532".

Case diameter just ahead of the solid web after firing was .5285" which is about the same expansion as the first load tested, right in there at .002" to .0025".

Primers good too.

 

[Sharps40]

For reference, a factory loaded 275g JHP was fired over the chronograph at 8f muzzle to start screen. Case was then collected and measured. Velocity was 860.5 FPS.

37 rounds of handloaded RimRock 255g LSWC were loaded over 6.4g Alliant Bullseye with the hard CCI LP Primers. 19 were fired over the chronograph. The remainder fired on target (7 yards) and steel, 7 to 15 yards.

The handload data is as follows:

50 GI Case, twice fired. 255g Rim Rock LSWC. 6.4g Alliant Bullseye Powder. CCI Large Pistol Primer. Cartridge Overall Length, 1.216". Crimp diameter at mouth of case, .525".

Accuracy was just fine. Feeding, firing and extraction of 37 rounds was perfect in the Glock 21 conversion package.

Chronograph data, 19 shots from 8 feet:

Shots 1-19: 889.8 fps/892.0/914.5/901.8/889.9/891.7/892.2/905.9/886.2/895.3/888.0/897.9/895.9/894.0/887.7/895.9/900.8/902.0/889.1

Ave: 895.3 fps

Hi: 914.5 fps

Low: 886.2 fps

ES: 28.3 fps

SD: 7.2 fps

AD: 5.5 fps.

Average body diameter (20 fired cases selected at random) of the 255g LSWC/6.4g BE loading was: .5316"

Average case diameter just in front of the solid head (20 fired cases selected at random) of the 255g LSWC/6.4g BE loading was: .5298"

Observations:

1. Ejection with 255g LSWC and 6.0g BE was erratic, cases landing in the 3, 6 and 9 oclock areas. Case mouths battered and bent. Ejection with the same bullet and 6.4g BE were consistently at 5 oclock, case mouths not battered.

2. The hard CCI primers are slightly flatter (though the edges are still nicely rounded) with both handloads than the factory loads that use the 275g JHP.

3. Recoil of the handloaded 255g LSWC is snappier than the Factory 275g JHP though still controllable. No worse than shooting a 10mm in my estimation.

4. Point of impact with the 255g LSWC/6.0g BE was accurate but a bit erratic even at 7 yards producing two distinct groups, one above the other with about 1.5" separation. Point of impact with the 255g LSWC/6.4g BE is spot on at 7 yards. Hitting even the 4" steels at 15 yards is pretty easy to do.

5. I suspect 950 FPS with this bullet is possible but given the recoil, performance and the measurements, I believe 6.4g Bullseye with the 255g LSWC will be my working maximum for this bullet/powder combination.