Glock 20 modifications for backcountry carry

[wymtnpounder]

I replaced the trigger connector on mine

 

[Tower]

I haven’t had any feed issues with Underwood or BB 220’s in my 29 Gen4 but I’ve only run a box of each through the pistol so far. I replaced the stock barrel with a threaded KKM and am using a 21lb stainless recoil spring assembly from Glockstore. The only mag modification I’ve done is to add a Pierce pinky extension to a couple of mags.

The only issue I’ve had was the very first box of S&B FMJ through the stock brand new pistol. Had 5 light primer strikes. I field stripped it, removed the Glock gold grease, cleaned and relubed and its run fine through the next 100 rounds of S&B.

 

[myalias789]

Have you called underwood? They are pretty helpful guys and have a lot of experience in this matter.

I’ve tested all of the heavy weights from underwood in two of my Glock 10mm’s and never had any issues with all factory components. Sucks this is happening to you.

 

[mcseal2]

Thanks. I have not yet contacted Underwood. I have the 22lb spring that should be in any day to try on order. I also ordered a box of 220gr Buffalo Bore HC ammo and a box of Underwood 140gr Extreme Penetrators. I'm going to see if one of those feeds fine. I still have a few rounds of the Underwood 200 and 220gr HC ammo to try with the 22lb spring also. I will hopefully find something that works. I'll contact Underwood after trying those if I still need to. If I end up having to go with the Extreme Penetrators and could have used stock everything I'll have wasted some money on this project. I'll post again after trying the other ammo and the 22lb spring.

 

[Fatcamp]

In all honesty the majority of gun hobbies are wasted money.

So there's that.

 

[mcseal2]

Good point. I did not plan on spending this much when starting this project, but I've been down that road before too. As long as I get it right before I'm done I'll be ok with that.

 

[Beendare]

Good thread, very informative to all who have contributed solid info.

a couple comments;
It seems that there is a small variation between these wide meplat hardcast bullets and its worth testing and experimenting to find the right combo for sure. Exact bullet dia is pretty critical with these Hardcast bullets it seems.

McSeal have you mic'd your bores? And mic'd the different bullets you have tried?

The Underwood and Double tap 200gr and 220gr show a penetration [over the Underwood 140gr.150gr] advantage in every test I've seen. More than a couple guys have better operation with the DT's.

I'm following this and thx to McSeal for starting this thread.

..

 

[mcseal2]

I have not mic'd the bores. I need to get batteries for my electric calipers if I get to town, they were dead when I got it out. The rounds drop into the chambers of both barrels with ease and show good accuracy with the KKM once I get them in the chamber.

I am hoping the different shape of the Buffalo Bore HC loads might make a difference. Midway did not have the Double Tap when I ordered or I'd have tried those too. I agree about the HC heavy bullets out penetrating the Extreme Penetrators, that's why I haven't tried them before. I saw the same in the tests I've been able to find. I don't want to go to them unless I have to.

Researching Buffalo Bore, Double Tap, and Underwood before starting this I saw a lot of positives for Underwood. That plus them being cheaper and me planning to shoot a lot of them started me in that direction. I might end up having to try a different brand.

We will see when my orders show up. Glad this thread is helping some people.

 

[mcseal2]

Well I just got off the phone with Underwood. They were very helpful, great customer service.

Basically after going through everything I've tried they said to try a 22lb and/or 20lb recoil spring assembly. Use the factory barrel for this and see if the 200 or 220gr HC ammo feeds. After that try the same with the +10% mag spring installed. If something works try it with the KKM barrel. They said KKM used to offer a bit of chamber beveling if you told them you planned to use a lot of hardcast ammo. If I find something that works in the factory barrel but not in the KKM it might need that.

I also asked them about the 140 extreme penetrator. He said in gel it gets around 36" of penetration compared to the 50" of the heavy hardcast ammo. He said the wound channel is substantially larger on the Extreme Penetrator. It just depends on what you are actually looking for from the bullet. If he was going to Kodiak Island tomorrow he said he would take his G20 and be comfortable with either. On a bear instead of a gel block he said he would expect 30" of penetration with a good wound channel more similar to that of a JSP bullet than that of a hardcast.

He said it's an excellent choice for someone who wants to run a completely stock G20 and have great feeding and performance.

Anyway figured I'd share that while it was fresh in my mind. I'm hoping the UPS truck beats the storm we have coming and I can try the ammo I have on order.

 

[Rob5589]

Picked mine up today and spent a solid 2 hours watching vids and reading tests. The HC out penetrates the EP every time. BUT, the EP reliably gets 25+ inches of penetration through every tested medium which would be more than enough to get to a bears brain, and then some. Are they as good as the HC? Nope. Will they take care of business as intended? It would seem so.

Price wise, however, the UW 200 grain HC is going to be the first "real" 10 mil I try.

 

[mcseal2]

That was my first choice and first try also. Hope it works for you. Enjoy the new gun!

 

[willisp.72]

I’ve had very similar issues with my gen 3 glock 20 that you describe. I never ran the underwood ammo, but really wanted the buffalo bore hard cast to work as it was easy to find locally. I experimented with all manner of recoil spring weights and the extra power magazine springs but never could get the reliability I wanted. I now run the double tap 200 grain with a 20 pound spring and have complete reliability with these loads as well as any hollow point self defense ammo or practice ammo I have tried.

 

[Jesse Jaymes]

For anyone shooting Lehigh.....point of impact....isn't the high speed 140 impact significantly different than a 220/200 HC?

You Glock 20 guys can't really even adjust your sights can you?

 

[Rob5589]

For anyone shooting Lehigh.....point of impact....isn't the high speed 140 impact significantly different than a 220/200 HC?

You Glock 20 guys can't really even adjust your sights can you?

Not without changing to an adjustable rear sight

 

[Fatcamp]

You can adjust horizontal by drifting the sight left or right, and vertical issues can be solved by sight post placement.

 

[Wrench]

Mine has Dawson precision adjustable target sights.

 

[Fatcamp]

Ya, I use fixed Dawson sights on my competition pistol. Fine product. Different height front site posts handle elevation issues, and they drift for windage. Night sights on my other guns.

 

[cubdriver84d]

Haven’t seen it mentioned yet, but grizzly cartridge co is loading a 200 gr WFNGC that looks very similar to the double tap bullet. Might be one to try. Was just at sportsman’s and they had a good stock. Curious if anyone has run them. Only found this thread so far http://10mm-firearms.com/factory-10mm-ammo/grizzly-200gr-wfngc/

 

[mcseal2]

Well I got them shot today.

The Buffalo Bore I shot first. I used the KKM barrel but stock everything else. I shot 5 with no failures to feed. The group is shown in the picture below. Not great accuracy, but I wasn't trying to milk all the accuracy I could from the gun. I was trying to shoot how I naturally fire the gun and see if it failed to feed. I shot with my normal grip and a fairly fast shot sequence, like I was shooting one of my rolling ball targets trying to keep it moving.


I did not shoot more of these rounds just yet. Nothing was really wrong but there was a heck of a lot of smoke from them compared to anything else I've shot. I think this may be due to the gun opening a bit early. I loaded 5 and tried the 24lb spring and got a jam first shot. I want to save the other 14 for when I get the 22lb spring in and see how they do with it.

I held at the bottom of the can. As the target says the center of my group is about 4" high and measures about 4". I used a tape measure and went roughly center to center of the farthest holes. Not real scientific.

Buffalo Bore has some stuff on their page for this ammo about recoil springs. Also I found under their FAQ section some info on firing hardcast through a Glock barrel that was interesting. Short of it is that it's fine according to the head of Buffalo Bore.

 

[mcseal2]

Next I shot the Underwood Extreme Penetrators. Again I used the KKM barrel, stock everything else. Again I had no failures to function. I shot 15 of these. I shot 5 at 20 yards first, then 5 at 15 yards, then 5 at 25 yards. The targets are pictured below.


I shot the left hand target at 20 yards first. I shot it like the target above, fairly quick and natural. I marked the holes and then shot again at 10 yards the same way. Both times I expected my first shot to hit higher and then adjusted my aiming point for the next 4 shots. That makes my group size double what it would have been without that first shot being so far out. This was the first time I shot these rounds and I thought they would hit higher with the light weight and high velocity. I was glad to see that they didn't. Recoil was comparable to the other Underwood ammo I've shot and there was little smoke. Pretty sweet shooting round really.

The target on the right is the last one I shot at 25 yards with the same EP ammo. They hit a bit higher that far out. I did a better job of holding them together knowing where to aim a bit more.

My sight picture on all these targets is holding the bottom of the cardboard or can, top of front sight level with the top of the rear sight.