Glock gen 5 17

I was shooting a match yesterday and had a few rounds make an oblong entry. Two rounds that I know of, possibly more. The holes were quickly pasted over so I didn't get to have a good look. I also had three consecutive misses on a steel target at 10 yards that I cannot account for.

I slugged the bore and the groove diameter measures .355" and my bullets were sized .356" The rifling is somewhat different on the gen 5 17.

Load is Lee 356-120-TC over 4.5 gr. Auto Comp, COAL: 1.030". Hardness is around 11. I'm getting moderate leading but nothing a copper chore boy over a brush doesn't fish out. Has anyone else had a chance to play around with the gen 5?

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There should be no leading at all. Size to .357 and try again.

If you're using Lee dies, be aware they only flair the case mouth and don't expand where the rest of the boolit sits. I switched to RCBS which do expand where the bullet sits and the case sizing down the boolit went away. Generally I size as large as the plunk test allows.

I started Powder coating all my cast boolits about 9 months ago. All leading in every gun from .40 S&W to .45-70 .44 Special/Magnum and .45 ACP magically disappeared.

The guns are 4 gen 3 Glocks, Kimber 1911, Ruger SBH and BH, S&W696, Marlin 1894 and 1895.

These guns vary widely in bore sizes and boolit fits. Makes little to no difference. The PC completely eliminates the lead to bore contact and thus the leading.

It was pretty cheap to get into and the benefits are no lube to deal with which equates to no possibility of powder contamination, or inadequate lube performance, and cleaning of all of the bores on all of these guns has been reduced to one clean patch to remove the powder fouling from the last shot fired.

Another benefit is that it increases the size of the boolits from .002-.004. So if you have moulds that are dropping undersized boolits they can be bumped up in size and then sized down to what is appropriate for your gun.

With Glocks the boolit fit is most important, and they will lead if it is not right. Erring on the large side is best and as long as the rounds feed into the chamber freely you are good to go.

Gen 5 Glocks have conventional rifling not the so called Polygonal rifling of the past. IE; the Lands are square cut as opposed to being rounded like previously made. This should make shooting lead boolits easier but I don't really know why, as I never had problems with any of mine.

Randy

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Originally Posted by bosterr

If you're using Lee dies, be aware they only flair the case mouth and don't expand where the rest of the boolit sits. I switched to RCBS which do expand where the bullet sits and the case sizing down the boolit went away. Generally I size as large as the plunk test allows.

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If you want to keep using Lee dies to load with (if that is in fact what you're using) you can swap out the 9mm expander plug in the expander die with one for a 38 S&W. You can order just the plug from the Lee website for really cheap. It'll expand down into the case further than the stock plug, and also just a touch bigger so there's no chance of swaging down your boolits when you seat.

This one fix solved pretty much all of my leading problems with 9mm

I'm using RCBS with a Dillon powder through belling die but thanks.

I've got several loads sitting on my reloading table, ready to test out in my new Gen5 17. I hope my Lee 120 TC powder coated bullet will shoot in it; it shot horribly in my gen 3 but perfectly through my KKM.

One interesting detail I ran into, make sure you do a plunk test when setting up your load for a gen 5. My COAL had to be 35 to 40 thousandths shorter than my OEM Gen 3 or KKM barrel. If you assumed that your normal OAL would work (a safe assumption between older models in my experience), that could account for the erratic issues.

I have high hopes for the Gen 5; I bought it to shoot cast and remain GSSF legal.

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Originally Posted by bosterr

If you're using Lee dies, be aware they only flair the case mouth and don't expand where the rest of the boolit sits. I switched to RCBS which do expand where the bullet sits and the case sizing down the boolit went away. Generally I size as large as the plunk test allows.

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That's not true. I just measured my Lee 9mm expander yesterday. The bullet seating part of the expander measured .354. If you are talking about the Lee universal expander, then I agree that only flares the case mouth.

What is different about the rifling? I hope they don't screw up a good thing. I love, love, love my Glock M20 Gen4 10MM.

I've shot that Lee bullet out of a few different Glock 9MM pistols. I had the same problem. Mine were keyholes and bouncing back off backstop due to tumble and yaw in flight. I was sizing at .356. I bumped up the diameter to .358 and it all went away and they were very accurate from that point on.

Just tested a few loads through my new Gen 5. All loads were:
Lee 120 TC, softish alloy, weighing 124 gr each. PC with Smoke's Clear, sized .357
COAL was a cartoonishly short 1.043"
Crimp 3.80
Blazer Brass, Federal SPP

Average velocities were:

3.8gr Sport Pistol 1082

4.0 Sport Pistol 1093

4.0 N320 1101

The 4.0 SP acted like it really wanted to group at 25 yards. I think a long day of work, plastic sights, and a heavy trigger could have all contributed to some fliers on my part. The good news is, almost no leading! It's not going to be as user friendly as my old KKM barrel, but I'm hopeful she can be made to shoot lead accurately with a little tinkering.

4.2 Sport Pistol over 124 Delta Precisions yielded a 3" 10 shot group offhand at 25 yards; I suspect the gun is mechanically capable of much tighter.

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Originally Posted by blue32

I'm using RCBS with a Dillon powder through belling die but thanks.

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You can get a Dillon powder through custom made to Lyman M die specs. In my limited experience, searinf our bullets this deep in a 9 is bad mojo if the case is just belled and not properly expanded.

I cast some more bullets but they barely mic at .358. I'll try it again this weekend.

Try seating to 1.055. You might be pushing it so far down in the case that the bottom of the boolit is getting pinched.

I know this is an old post but I wanted to give an update. I tried sizing the Lee to .358 and putting the expander deeper into the case but I still got leading. Ended up going the PC route and settled on Eastwood light purple and neon green. For whatever reason the green doesn't coat as well but performance is the same. Sized to .358 and the accuracy came back. I've settled on a COAL of 1.025 (any higher and I didn't get reliable chambering) and worked up a load to 4.7 gr. Auto Comp which gives 1,138 fps. Thanks for the help!

Attachment 261892

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Originally Posted by blue32

I know this is an old post but I wanted to give an update. I tried sizing the Lee to .358 and putting the expander deeper into the case but I still got leading. Ended up going the PC route and settled on Eastwood light purple and neon green. For whatever reason the green doesn't coat as well but performance is the same. Sized to .358 and the accuracy came back. I've settled on a COAL of 1.025 (any higher and I didn't get reliable chambering) and worked up a load to 4.7 gr. Auto Comp which gives 1,138 fps. Thanks for the help!

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I had horrible key-holing with that mold in a Gen 4 G17. I dumped the mold for the 125gr 2R and am having much better luck. My favorite .40 mold is theLee 175 TC, so I was hoping for greatness from the 120 TC, but it didn’t work out that way.

I could never get that boolit to work on my glock gen 3
I switched to using a 120 grains TC rcbs mold cast 357 and the problem was solved
I sold that mold

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Originally Posted by 44MAG#1

What is different about the rifling? I hope they don't screw up a good thing. I love, love, love my Glock M20 Gen4 10MM.

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The Gen5 rifling for the 9mm barrels is sort of a combination of conventional rifling and polygonal rifling; it's a bit difficult to describe.
The bottom the groove is square cut, like conventional rifling. The lower corners of the groove are sharp. The tops of the lands are a bit rounded, like the old polygonal rifling Glock used.
Glock didn't screw up a good thing, at least in the 9mm barrels. I can't speak to cast but with FMJ the Gen5 will SHOOT !

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Originally Posted by blue32

I know this is an old post but I wanted to give an update. I tried sizing the Lee to .358 and putting the expander deeper into the case but I still got leading. Ended up going the PC route and settled on Eastwood light purple and neon green. For whatever reason the green doesn't coat as well but performance is the same. Sized to .358 and the accuracy came back. I've settled on a COAL of 1.025 (any higher and I didn't get reliable chambering) and worked up a load to 4.7 gr. Auto Comp which gives 1,138 fps. Thanks for the help!

Attachment 261892

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Coated boolits made my life much simpler when loading 9mm