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Old 07-25-2011, 15:04   #73
Blazin' 10mm x2
GTRhino24's Avatar
Join Date: Jun 2011
Location: Hoover, AL
Posts: 193
Originally Posted by ModGlock17 View Post
I ran an experiment With Blue Dot, trying to find a comfortable operating range on my G20 and G29sf.

Condition: 93F, about 150ft elevation above sea level

Toy elements: G20, G29sf, CCI primer 300, Blue dot, once fired Starline brass, Berry flat nose bullet 180gr, Chrono F1. Also chrono'd BVAC and Georgia Arms 165gr.

Experiment: 10.0gr, 10.2gr, 10.5gr, 10.8gr, BVAC, GArms each had 5 samples for each gun.

Chrono placed about 10ft out, no choice... had to get out of the roof area.

G20 ave result:
10.0 => 1070fps std8.6, 458 ft-lbs
10.2 => 1073fps std7.3, 460 ft-lbs
10.5 => 1098fps std6.6, 482 ft-lbs
10.8 => 1135fps std30.7, 515 ft-lbs

BVAC 180gr => 1056fps std 6.1, 445 ft-lbs
GArms 165gr => 1226fps std4.9, 551ft-lbs advertised 1250fps at muzzle.

G29sf ave result:
10.0 => 995fps std14.0, 458 ft-lbs
10.2 => 1005fps std15.0, 460 ft-lbs
10.5 => 1063fps std9.9, 482 ft-lbs
10.8 => 1076fps std10.6, 515 ft-lbs

A few conclusions
1. Speed loss from G20 stock barrel to G29sf stock barrel was around 60fps.
2. Powder weights for 180gr plated bullet from 10.0gr to 10.8gr are rather anemic. Extrapolate to 11.0gr, and perhaps 11.2gr should be the next experiment. That should make it good for target shooting, not stressing the gun too much.
3. Speed gain on G20 is still increasing at 10.8gr of BlueDot.
4. Standard deviation trend is tightening on G20 (with exception of one datapoint at 10.8gr) with higher powder weight.
5. G29sf generally results in wider standard deviation, probably shorter barrel causing less consistency.
6. GeorgiaArms has pretty good stuff at just over 40cents/round, for a factory round.

Note: G29sf had just a couple hundred rounds so far, can be considered "not fully broke-in" as yet. But including it for 11.0+ gr experiment is worth doing.
+1 on the write up! Same guns, bullet weight, primers, brass, and powder that I use so this is especially helpful. I look forward to the results north of 10gr! 10.5 is my target round. Thanks again! Oh, COAL? I set mine at 1.255 as it seems to feed a bit better than 1.260.
G26, G29SF, G20SF

Last edited by GTRhino24; 07-25-2011 at 15:05..
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