Author Topic: G20-SF; 180gr Where I'm at so far.. 2012  (Read 336 times)

RDub01

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G20-SF; 180gr Where I'm at so far.. 2012
« on: September 01, 2017, 11:22:39 PM »
Hello
This was posted back in '12, but since then the original website changed and is not capable of hosting a post like this. Also I had to change picture hosting sites. So I would like to keep it over here. Thanks.



Well after shooting this G20-SF for a couple months, here is where I am with it..

I started out with the Speer 180gr TMJ, Rem 9½ primers, and Starline cases.  I used WLP and CCI 300’s with AA#9. Everything was seated at 1.26”
Next, I tried some choice loads with the ISMI 22# Spring.

Then I tried the 180gr Hornady XTP with the stock spring and the ISMI spring.

I drew up a small graph to get a better bird’s eye view of all this. Color code is on top. The red (F) means factory spring.



My goal was to come up with a 1250fps load, but I found that getting there was not easy with the Speer bullet.
After compiling all the case head data, it appears to me that when case heads start getting into the .4345” range, pressure is up there where smileys start showing up.

 







Powders:

Power Pistol;
Produced some of the best groups in the trials.  Notice no velocity gain from 9.0 to 9.2grs. This usually means time to stop, so I did.
9.0grs provides a good accurate all-round load at 1200fps.

8.2grs- 1115 fps      (#11)
8.4grs- 1141 fps      (#12)
8.6grs- 1155 fps      (#13)
8.8grs-1178 fps   .4337, .4333, .4335, .4337, .4337       (#14)
9.0grs- 1197 fps   .4339, .4336, .4335, .4336                   (#4)
9.2grs-1198 fps   .4346, .4336, .4340, .4338, .4335        (#4)

180gr Hornady XTP..
9.0grs- 1208 fps   .4343, .4336, .4343, .4340, .4333        (#20)


800-X;

Virtually no velocity gain from 9.9grs to 10.2grs. Good solid powder for the 10mm.
10.1grs with the Hornady XTP duplicated the Buffalo Bore 180gr JHC load.  (#2)
http://www.handgunforum.net/range-report/32001-glock-20sf-buffalo-bore-180grjhc.html

9.0grs- 1135 fps    (#6)
9.3grs- 1167 fps     (#7)
9.6grs- 1197 fps      (#8)
9.9grs- 1232 fps   .4335, .4338, .4335, .4337, .4337       (#9)
10.2grs- 1239 fps   .4333, .4342, .4337, .4334, .4342           (#9)

ISMI 22# Spring
10.2grs- 1234 fps   .4339, .4341, .4338, .4337, .4330            (#6)

180gr Hornady XTP..
10.2grs- 1273 fps    .4343, .4340, .4335, .4340, .4336     (#22)

ISMI 22# Spring
10.1grs- 1251 fps   .4340, .4330, .4339, .4338, .4340   (#12)

3N37;
Got a very nice group with 9.3grs. It looks like 9.3 is right at the ragged edge with pressure.
Also, 9.3grs come very close to duplicating the Winchester 175gr ST load which is loaded with 9.3grs of something.
http://www.handgunforum.net/range-report/31846-new-glock-20sf-win-175gr-st-report.html
10.0grs is Speer’s maximum load but it is way too hot for this gun.

8.7grs- 1113 fps   .4336, .4327, .4332, .4335, .4339                   (#1)                       
9.0grs- 1149 fps   .4341, .4333, .4339,  (lost two cases)              (#2)
9.3grs- 1187 fps   .4342, .4337, .4341, .4340, .4337                    (#3)
9.5grs- 1195 fps   .4345, .4343, .4338, .4344  (lost one)              (#5)
10.0grs- 1239 fps   Smileys.. too hot.                                              (#6)

LONGSHOT;
The charges I tried produced some very high velocities, but at the cost of high pressure.. At least that is what the case heads were telling me.
Initially, I shot some good groups with Longshot but haven’t yet been able to repeat this.

8.9grs- 1221 fps   .4343, .4341, .4338, .4335, .4338   (#5)
9.2grs- 1246 fps   .4339, .4341, .4344, .4336, .4340   (#10)
9.3grs- 1264 fps   .4349, .4345, .4341, .4338, .4339    (#3)
9.5grs- 1275 fps   .4341, .4343, Smiley, .4348, .4344   (#15)

ISMI 22# Spring
8.9grs- 1209 fps    .4340, .4342, .4339, .4338, .4340     (#7)                                                                                                 
9.2grs- 1241 fps    .4340, .4341, .4343, .4340, Smiley    (#8)

180gr Hornady XTP..
9.3grs- 1263 fps   .4353, 4347, .4345,  Smiley, .4341   (#3)

ISMI 22# Spring
8.9grs- 1239 fps     Smiley, .4347, .4342, .4342, .4350      (#11)


AA #7;
11.0grs produced a nice group save the flyer.. after that so-so.
There seems to be a significant pressure spike from 11.5 to 12.0grs.

11.0grs- 1123 fps                                                           (#16)
11.5grs- 1161 fps   .4332, .4333, .4330, .4336, .4332       (#17)
12.0grs- 1203 fps   Smileys..  Too hot for this gun            (#11)

ISMI 22# Spring
11.6grs- 1152 fps   .4337, .4335, .4336, .4335, .4333      (#10)



Blue Dot;
I was very surprised at how slow the Blue Dot loads were. I was expecting something more..  I worked up to 11.4grs and the case heads are showing mild pressure, at least with the Speer bullet.
Very little velocity gain from 11.1 to 11.4grs.
This powder might do better in a 6” barrel.

10.5grs- 1096 fps   (#21)
10.8grs- 1137 fps   (#22)
11.1grs- 1187 fps   .4335, .4333, .4335, .4331, .4339    (#23)
11.4grs- 1191 fps   .4333, .4332, .4339, .4334, .4336    (#10)

180gr Hornady XTP..
11.4grs- 1203 fps   .4344, .4337, .4339  (lost two)        (#23)


AA #9; 
Well it’s true, you get some respectable velocities with lower pressures. 
14.9grs with the Hornady bullet seated to 1.26”, the powder will push the bullet back out a little bit.

14.9grs- 1219 fps (CCI 300)  .4339, .4333               (#12)

ISMI 22# Spring
14.5grs- 1194 fps  (WLP)  .4335, .4330, .4331, .4336, .4332,     (#9)

180gr Hornady XTP..
14.9grs- 1266 fps (CCI 300)   .4340, .4346, .4340, .4339, .4342      (#24)

ISMI 22# Spring
14.5grs- 1229 fps   (WLP)   .4337, .4336, .4338, .4338, .4335    (#13)


A little later I got a chance to shoot some more 180gr Speer TMJ’s, this time with some N-105, 3N38 and Silhouette.  Bear in mind that this round was shot when it is significantly cooler than it was last summer and fall.. So I’m sure this will effect velocities and pressure.. And maybe to some extent, what the groups look like.
I’m not sure why the groups are so high and left..  This gun didn’t care much for N-105.
Anyway, here is the target;





Glock 20SF with factory barrel and spring
Rounds were seated to 1.26” COL
Circles are 5½” at 25 yards
Shooting was done off of a Caldwell Pistol Rest
Velocities taken with an Oehler Mod 33 chronograph. Sky screens centered 8’ from muzzle.
Data on targets;
Average velocity
Velocity spread
Standard deviation
temperature

3N38
11.3grs is about max in this gun, maybe a bit less in warmer weather.
I had an erroneous chrono reading on the 11.3gr string that I didn’t catch, which screwed up the average, but I recall seeing velocities in the low 1200’s
10.4grs   1103fps     minimal expansion
10.7grs   1138fps     .4335, .4335, .4335, .4330, .4336
11.0grs   1167fps    .4339, .4335, .4336, .4337, .4336
11.3grs   1200fps     .4340, .4338, .4339, .4340, .4342
11.6grs   1240fps     .4339, .4346, .SMILEY, .4345, .4339


N-105
11.1grs was somewhat compressed with the Speer 180 TMJ and 12.0grs was very compressed.  N-105 is an extruded powder and it doesn’t meter as well as some others.
11.7grs is as far as I want to go here..  12.0grs gave head expansion larger than I want to go.
Both 3N38 and N-105 maxed out at about 1200 fps in the factory barrel.
11.1grs   1153fps     .4334, .4334, .4332, .4340, .4330
11.4grs   1183fps    .4336, .4337, .4339, .4332, .4335
11.7grs   1215fps    .4336, .4344, .4340, .4336, .4341
12.0grs   1240fps    .4342, .4346, .4344, .4345, .4336

SILHOUETTE
Ramshot is listing 8.4grs as a maximum load with a 180gr bullet. Case expansion is indicating this is a rather mild load.  Watching expansion I took Silhouette up to 9.0grs. Four of five cases at 9.0grs showed acceptable expansion, except the one .4345”, which is where I stop.
8.4grs   1093fps        .4337, .4334, .4331, .4334, .4333
8.6grs    1117fps      .4334, .4333, .4331, .4337, .4336
8.8grs    1135fps      .4339, .4341, .4335, .4342, .4336
9.0grs    1161fps      .4336, .4345, .4342, .4338, .4341

Here is the latest graph;



Here is all the data on Excel.






Anyway, that’s where I’m at with this particular gun..  More to come.
« Last Edit: September 01, 2017, 11:38:08 PM by RDub01 »

tommac919

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Re: G20-SF; 180gr Where I'm at so far.. 2012
« Reply #1 on: September 02, 2017, 05:10:47 AM »
Thank you , some nice work

sparkyv

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Re: G20-SF; 180gr Where I'm at so far.. 2012
« Reply #2 on: November 12, 2017, 05:19:35 PM »
Very useful body of work, RDub01.  Thanks for sharing.  Thus gives me some confidence to try some loads I've been considering, as I don't have a chrony.  I look forward to your updates.