G20 vs Storm Lake chamber dimensions

[DavidinSA]

Okay everyone.

This is related to another thread but I thought I would start a new one for all others to see.

Got a chance to take some quick measurements on the chamber of my G20 factory barrel and a Storm Lake Barrel.
Here are the results.

Factroy Barrel
0.4259" at step before bore
0.4316" approx. half way in the chamber
0.4350" just past the chamfer on the feed side

Storm Lake Barrel
0.4245" at step before bore
0.4270" approx. half way in the chamber
0.4288" just past the chamfer on the feed side

All the cases that I measured were 0.4185" - 0.4195" O.D.

I don't know if these are acceptable dimensions or not.
If anybody has info from Glock on their chamber specifications I would appreciate you posting them here.

You can see why if you have an overpressured round or weak/thin case, that in the Glock barrel there is a higher chance of damaging KB.
I had not realized how loose of tolerence there was on the chambers vs. case size.
You can also see why the Glocks will fire and operate in the worst conditions and with many different cartridges.

Although I have shot my whole life, I am just getting "into" firearms and their design.

Any thoughts, feel free to post.

Thanks
David

[ppro]

David in SA

"Although I have shot my whole life, I am just getting "into" firearms and their design."

Better late than never :cool:

I am not sure which dimensions you are wondering about being acceptable, but as you indicated, the Glock is designed to handle a wide range of ammuniton in the worst conditions.

It is nice to have options and many of us do opt for tighter dimensions such as the Storm Lake barrel.

regards

Paul

[DavidinSA]

The reference was to the chamber dimensions.
Another thread was concerned with the KB's from some ammo and it came up that maybe Glock had some out of tolerence chambers that got past QA.
I doubt they ever would make it past QA but you never know.
So I decided to see what the actual dimensions were and was very surprised to see the difference between the Storm Lake and the Glock.
Just trying to learn all I can.

Thanks
David

[ppro]

DavidinSA

I haven't seen that much on Glock chambers that have been measured, but it would be interesting to see some comparisions of actual measured chambers and also the differences in the older Glocks vs the newer ones.

Here's a link to the right way to start and possibly some others on the site would like to check theirs also and post their results.

http://www.midwayusa.com/rewriteaproduct/462291

Paul

[DavidinSA]

Interesting product.
I will order some and see how well it keeps it's tolerance.
As long as I use the same material and method for each barrel, the comparison will be accurate and relative to each other.

On my numbers earlier, I used a NIST traceable digital bore micrometer calibrated to (+)(-) 0.0001".

What I might do this summer is start asking around and see if other shooters are willing to let me measure their barrels.
This way I could start building a database correlating barrel manufacturing date/# of rds that have passed through the chamber/firearm model #.

Could be an interesting project.
Probably not very valuable but one never knows what might turn up until you do it.

Thanks for the info.
I will keep you posted if I come up with anything interesting.
David

[Crazy Ed]

I put a KKM in my G20 right from the start. Just by putting rounds in the chambers and shaking them (barrels removed from gun) I was really impressed with how much more support the KKM offered. The stock barrel was really loose. I'd be interested in seeing what you find out regarding tolerance/specs for the stock barrel.

Ed

[klmmicro]

Originally posted by Crazy Ed
I put a KKM in my G20 right from the start. Just by putting rounds in the chambers and shaking them (barrels removed from gun) I was really impressed with how much more support the KKM offered. The stock barrel was really loose. I'd be interested in seeing what you find out regarding tolerance/specs for the stock barrel.

Ed

Shoot 25 rounds from each barrel (from the same box of ammunition) and keep them seperated. Mic the brass and you will see that the KKM barrel keeps the cases much closer to there unfired dimensions.

I also switched to a KKM barrel, but I do not mind shooting the pistol with the stock Glock barrel in it either. My switch was more for brass preservation and lead shooting as I reload.

[Crazy Ed]

I checked the brass through the KKM yesterday. There were no bulges at all. The Double Tap brass even looked brand new still. The CCI Blazer casings that came with the gun looked way too bulged in different areas of the case.

Ed

[ppro]

Crazy Ed

I get the same results with the Storm Lake barrels. Brass looks just fine especially compared to the factory Glock barrels and this is also with Double Tap.

And (a plus for me) the Storm Lake barrels handle lead VERY well.

Paul

[Crazy Ed]

Some day this week I'm taking the new G29 out. I already replaced the stock barrel with an EFK barrel. I love shooting Double Tap so to me it's not worth it to have to worry about the stock barrel performance. I don't like them little semi-smileys at all.

Ed :supergrin:

[Crazy Ed]

Originally posted by ppro
Crazy Ed

I get the same results with the Storm Lake barrels. Brass looks just fine especially compared to the factory Glock barrels and this is also with Double Tap.

And (a plus for me) the Storm Lake barrels handle lead VERY well.

Paul

Paul, did you replace your stock recoil spring with a 22#? I'm just curious. When I initially took my G20 out it was slinging brass all over the place. It was funny, the other day my wife was driving the truck and had to put the windshield wipers on. Low and behold there was a spent 10mm casing caught in the wiper blade LOL. Since then I read that Mike at DT recommended a 22# so I did that. I'll be shooting her again Saturday, along with the new G29. I already replaced the recoil spring and guide rod in the 29 with a Wolff steel replacement rod and 19# recoil spring.

Ed

[Reyn]

Ive got a 22lb spring in mine. Mine still kicks the brass pretty good. I havent compared with the factory but it definately doesnt fall at my feet.

[DavidinSA]

I'm running 24# in my G19 and G20, a 22# in my G27.
All have been working well so far with a large variety of ammo going through them.

Currently I am in the process of making a jig to measure the installed spring tension on all my Glocks at various slide positions.
I will post results when I get them.


David