Georgia Arms G10B 180gr Speer Bonded Hollow Point

[DAVIDF]

This past weekend, my wife and I chronographed the Georgia Arms 10mm 180gr Speer Bonded Hollow Point (Gold Dot) load http://www.georgia-arms.com/new-10mm-180gr-speer-bonded-unicore-hollow-point-p/. This has been my carry load in both of my Gen 3 Glock 20's.

Chronograph was a Competition Electronics ProChrono Digital. Measurements taken from 10ft. Temperature 71 degrees with 85% humidity when we started and 74 degrees with 78% humidity when we finished, pressure was 29.9 inHg, 33' or thereabouts elevation. Firearm used was a Gen 3 Glock 20 with stock barrel.

First string was with the stock RSA:

1-1136             6-1116
2-1138             7-1112
3-1124             8-1137
4-1131             9-1116
5-1126            10-1130

Hi-1138 Lo-1112 Ave-1126 ES-26 SD-9

Second string was with a Wolff Gunsprings steel guide rod & 20lb spring:

1-1148          6-1140
2-1146          7-1148
3-1134          8-1147
4-1150          9-1141
5-1159         10-1140

Hi-1159 Lo-1134 Ave-1145 ES-25 SD-6

Third string was with the Wolff Gunsprings steel guide rod & 24lb spring:

1-1134           6-1134
2-1137           7-1153
3-1145           8-1150
4-1135           9-1144
5-1138          10-1153

Hi-1153 Lo-1134 Ave-1142 ES-19 SD-7

We didn't nearly see the advertised velocity of 1200fps, nor the 1220fps that Intercooler saw. However, it is a very consistent and accurate load. At the end of our session I did a 5 shot group of 2 3/4" off of a mediocre rest at 40 yards. That is the only group I shot that day with that load, but seems typical of this load.

I found that my main carry magazine for this particular 20 was not functioning well at all with this load. I was seeing failures to feed every few rounds. The nose of the bullet was either lodging against the chamber on the left side or nose diving into the feed ramp. It performed the worst with the 24lb spring. However, I have found previously that it doesn't always like the 24lb spring no matter the magazine with 180gr loads that are over 1100fps. The 24lb spring works fine with very lite 10mm loads and 40 S&W loads. The 20lb spring worked the best with this magazine, but still had some issues. Good thing is that with these malfunctions with a 20, they are extremely easy to clear. Simply pulling back slightly on the slide and either easing it forward or letting it slam will allow the bullet to feed. I have replaced the springs of three of my magazines, including this one, with +10% extra power springs from Wolff Gunsprings. I'll give these a test next time I am at the range.

I don't think the lower velocity I saw was due to inaccuracies with my chronograph as I also tested a Speer Gold Dot 9mm load and saw slightly higher velocities than their advertised. Other chrono tests of that same load I have seen, showed velocities right near the advertised.

I am liking the Wolf Gunsprings guide rod with the 20lb spring and now leaving it in this 20 for carry purposes. I have a couple of other weight springs I may try, a 22, 19, & a 17lb. I may have to buy a second guide rod and several sets of springs for my other 20.

[The_Shadow]

Good report David!  I run my 20SF with the Wolff non captive 22lbs spring.  I have to wonder if Georgia Arms (10mm 180gr Speer Bonded Hollow Point) lighten their loading or changed powders with that particular loading?

Here is what was in the Georgia Arms 180gr Speer GDJHP+P
Ballistics Information: 10mm Auto
Muzzle Velocity: 1200 fps
Muzzle Energy: 575 ft. lbs
Brass Make/Headstamp: Underwood - Brass
Bullet Make/Weight/Construction/Info; Length 0.6355"/Dia. 0.4000": Speer 180gr. GD JHP HP depth 0.1220" HP width 0.2240"
Actual weigh 180.2 grains  Crimp Diameter 0.3945"
C.O.A.L.: 1.2410"
Primer: Nickle color
Case: Diameter 0.4215" Crimp Diameter 0.4205" Length 0.9870"
Powder Description/Positive ID/Type/Charge Weight: LongShot  8.4 grains

[Intercooler]

Hmmm.... These were the 1200 version too huh? Could you send one to The Shadow for pull-down?

[DAVIDF]

Intercooler,

I would be happy to. It will be a few days before I am out of the house. But, that would be good to see the difference from the ones he pulled down before. And, yes these are the 1200fps version.

The_Shadow,

Weren't the cases Starline? The ones I have use Starline. C.O.A.L. is just a tiny bit longer at 1.242. Every one that I have measured was at that length. Everything else seems to be the same.

[Intercooler]

I will look tomorrow and see what I have in GA. Maybe I can send you a few of mine if I have any.

[The_Shadow]

I have some Georgia Arms 155 and 180 grain loading that are posted in the pull downs, both had Hodgdon LongShot powder.

[DAVIDF]

Yes, I have the link to your pulldown of those saved. I'll send you those shortly when I can get out of the house. I don't see how this lot is loaded with 8.4gr of Longshot. My hand load with 8.0gr of Power Pistol and an X-Treme 180gr HPCB bullet matched the velocity. However, I had a horrible ES & SD. I think my scale is very erratic and I will be buying another.

[DAVIDF]

I just looked back at DRSJR1969's data sheet and video https://www.youtube.com/watch?v=BEPtBFA3pk4. That was posted on Apr 3, 2012. He saw the same velocities out of his Glock 20 that I saw with mine with the stock RSA but a little greater velocity spread.

1-1141
2-1133
3-1117
4-1108
5-1142

AV-1128 ES-34

[pacapcop]

Spring to heavy for load. IMHO