10mm G29 vs. G20 Ballistics?

[gbran]

Decisions, decisions. I spend a lot of time in the CA mountains and usually have a big bore handgun for self defense with me. I'm looking at the 10mm for a compromise in size and power. I want the most punch in the smallest, lightest package I can find. What I can't find is the ballistics out of the G29 3.78" barrel vs. the G20 4.6" barrel. All the Double Tap ammo data is for the G20.

Does anybody know how much performance is lost in the shorter barrel?

 

[alpha6164]

I am sure you already know this, but you can just roughly deduct ~50ft/sec for every 0.5" shorter barrel. This should give you a better idea.

 

[duncan]

The G29 will be what I carry instead of my G20.

 

[Dr_2_B]

Alpha, I hadn't heard this. Is it well-documented? Pretty standard?

Also gbran, if I were in your place, I'd seriously consider choosing the best of both worlds and get the G29, adding a longer replacement barrel to put in for the backwoods stuff. Ideal gun for CCW with the regular barrel and ideal gun for backwoods carry with the longer barrel.

You've got me thinking about it as I own all 3 of the Glock .45s but I don't own a 10.

 

[gbran]

matheath

Re; longer barrel. Are you saying I can get a longer (G20?) barrel in the G29? If so, this has just solved my delimma. I'll get the G29 and a second barrel. Thanks. BTW, I have a G26 and a G30 already.

 

[duncan]

The 10mm Glocks are nice because you can find aftermarket barrels to suit your needs.

Can't wait to pick up my G29!

 

[alpha6164]

Alpha, I hadn't heard this. Is it well-documented? Pretty standard?

Matheath, it is pretty well documented. I have seen several review articles that were about ammunition testing, and had mentioned that for every 0.5" that the barrel is shorter you lose about ~50ft/sec in velocity. Now, I don't think you can extrapolate a ballistic from a 4.5" barrel all the way down to a 2.5" barrel. Because I am sure at some point the barrel is short that the effects are more than the 50ft/sec. But if you have numbers for 4.5" barrel you should have no problem extrapolating that to a 3.8" barrel. Just take about 70-80ft/sec off the longer barrel numbers.

 

[Dr_2_B]

Gbran,

Check me on it, but many of the models allow for this, i.e. you can use the longer barrel in the shorter gun with shorter frame. The barrel simply protrudes an inch or so. But they're not all interchangeable. Do a little research before you buy.

 

[harrygunner]

G29 data I've noticed for DT ammo

Mike McNett of Double Tap Ammo has posted groups or individual chrono results for the Glock 29 on:

http://www.10mmtalk.com
http://www.glocktalk.com/forumdisplay.php?forumid=38

I collected Mr. McNett's data for my personal information.

I have a G29 and DT's 180gr GD ammo as well as some DT WFNGC Hardcast 200gr ammo for the woods.

If I noticed multiple values that were clearly within a standard deviation, I recorded the average of those values.

135gr JHP - 1520fps
155gr Gold Dot - 1429fps
165gr GSHP - 1336fps
165gr Gold Dot - 1348fps
180gr GSHP - 1261fps
180gr Gold Dot - 1242fps
180gr FMJ Match - 1198fps
200gr FMJ/FP - 1203fps
200gr XTP - 1180fps
220gr FP - 1074fps
200gr WFN Beartooth - 1233fps

Mr. McNett states there is an average 60 ft/sec drop in speed from a G29 compared to a G20 somewhere in those web sites.