G20SF Keyholing!

[jazzsax8]

Just picked up a nice G20SF that had less than 300 rounds through it.  Stock RSA and barrel.  First trip to the range with some of my tried and true loads of 9.0 Longshot with the X-Treme 200gr bullet.  In this new pistol I worked up test loads starting at 8.4, 8.6, 8.8 and 8.9 before trying the 9.0gr that had been max in some other aftermarket barrels in my G29SF.

Now the bad news.  ALL of the groups were keyholing at 20 yards producing average groups from 15 to 17".  I had only shot this bullet/powder through aftermarket barrels where it was tough to get a group larger than 3" 5 shots at 25 yards.  Some went as small as 1 7/8"!  Its almost like this factory barrel will not be made to work with this plated bullet using any combination of powders etc.  I use all of the loading tricks learned on this site (thanks much as I was only a heavy crimping revolver loader before getting the 10mm Glocks a year ago).

I do have some Berrys 180's, X-Treme 220's and XTP's in 200gr to try before I give up and buy another aftermarket barrel.  I also have some Rim Rock 220's that leaded everything I tried them in even at sedate velocity.  I would imagine non-plated bullets will work in this barrel just fine and I would like to keep this one stock for reliable woods carry.

What are your favorite plated bullet loads (X-Treme like mine) you are using successfully in a stock G20 barrel?

[The_Shadow]

jazzsax8, it is possible the plating could be the problem.  The poly rifling is different than conventional and the smoother surfaces tend to roll the bullet surfaces.  You may want to measure the X-Treme bullet diameters.  The actual bullet diameter size is also important, as most Glock factory barrels are like 0.4020".  I have had good results using my own cast bullets sized at 0.4015" and carnuba red lube, but I am wanting to try the powdered paint coatings on my bullets.  I just haven't got this project rolling yet.    I shoot them from G-20SF and G29 factory barrels.

I have measured Nosler bullets and found them to be small at the 0.3990" to 0.3995" and some meeting the 0.4000".

Inspect the bore and clean if necessary, I lightly lube my barrels with Hoppes' oil (two drops on a patch wrapped around the brush and stroke the bore changing the position.

Maybe the Hornady XTP will show you better results.

Best regards!

[tommac919]

What are your favorite plated bullet loads (X-Treme like mine) you are using successfully in a stock G20 barrel?

My most commonly fired round is the Xtreme 180 heavy plated fp with Blue Dot 10.2-10.4gr in a stock G20-g3.
At 50ft, handheld with 5 inch group, no problem at all  re tumble.  ( the lack of close grouping is me not gun as on a sand bag it is better )

I don't know if the 200s are heavy plated but it may make a difference

I have used XTPs in 180 and 200 , remington  fmj  and also  montana gold 180s .. haven't seen any diff as I can tell tho shooting at a slight shorter distance than your  using.

Edit;
Went and measured a about 10 xtreme 180 heavy plated.. 9 came in at   .4005 ( one that was .401 ) , so I would say former

[sqlbullet]

jazzsax8, it is possible the plating could be the problem.  The poly rifling is different than conventional and the smoother surfaces tend to roll the bullet surfaces.  You may want to measure the X-Treme bullet diameters.  The actual bullet diameter size is also important, as most Glock factory barrels are like 0.4020".  I have had good results using my own cast bullets sized at 0.4015" and carnuba red lube, but I am wanting to try the powdered paint coatings on my bullets.  I just haven't got this project rolling yet.    I shoot them from G-20SF and G29 factory barrels.

I have measured Nosler bullets and found them to be small at the 0.3990" to 0.3995" and some meeting the 0.4000".

Inspect the bore and clean if necessary, I lightly lube my barrels with Hoppes' oil (two drops on a patch wrapped around the brush and stroke the bore changing the position.

Maybe the Hornady XTP will show you better results.

Best regards!

This.  Oversize groove diameter + plated and possibly slightly undersize bullets.

[tommac919]

Went and measured a about 10 xtreme 180 heavy plated.. 9 came in at   .4005 ( one that was .401 ) , so I would say former

[The_Shadow]

Yes, I have heard of many have good results with the X-Treme bullets in their guns, even Glock factory.  If it were just accuracy issues it could be a locking block or slide stop issue...but that doesn't explain the keyholing!

[jazzsax8]

Measured 10 each of the X-Treme 200 & 220gr bullets and they are ALL consistent at .400!  Slugged the G20 barrel and it is .4015.  I imagine a cast coated bullet around .402 would be a good place to start.

Looks like I am going to need to get all of my plated undersized bullets together and pass them on with USPS shipping!  If anyone has some heavy 200+ grain bullets to trade, I would love to hear from you.

Marshall

[The_Shadow]

You might want to hang on to them in case you get another 10mm or AM BBL with conventional rifling to run test with.
You could even powder paint coat them an test as well.

[sqlbullet]

Powder coat will add 0.003"-0.005".  That would probably address the issue with minimal fuss.

[jazzsax8]

While I like your powdercoat idea I'm not sure I want to hassle with 1500 bullets when I probably will have no intention of continuing to use them in the same format even if they work. My G 20 came with a LWD 40 Smith and Wesson barrel that might be able to be used but these bullets are a little heavy for that case. If I want to shoot wimp loads I just get out the 9mm.

Again the real question is does anyone have a $0.10 bullet that works in the standard Glock barrel?  I don't mind using a .25 bullet for carry but need something cheap and accurate for plinking/training.

[PCFlorida]

Wideners has Armscor 180 FMJ $128 / K shipped. My math that says 7.8125 cents each. I'm on my 2nd or 3rd thousand, they shoot well out of my guns. Including my Glocks (20 and 29)

https://www.wideners.com/itemdetail.cfm?item_id=100001568&dir=278|281|1082|1144

[BEEMER!]

Wideners has Armscor 180 FMJ $128 / K shipped. My math that says 7.8125 cents each. I'm on my 2nd or 3rd thousand, they shoot well out of my guns. Including my Glocks (20 and 29)

https://www.wideners.com/itemdetail.cfm?item_id=100001568&dir=278|281|1082|1144

Your math is not quite right, it's 12.8 cents each.

[PCFlorida]

LOL, so it is.

Still a good price though.

[BEEMER!]

I agree.   

[sqlbullet]

Breaking the ¢10 barrier is going to be a cast bullet, probably powder coated to feed a Glock.

I am back to thinking a bottle of Harbor Freight red and tumble and bake solves your issue pretty easily.