Vectan GM3 Initial Impressions

[jonp]

I recently bought a couple of pounds of Vectan from Grafs to try out in a pistol. After some research I bought a bottle of GM3 and one of A1. The GM3 was first up.

Its burn rate on the chart is right next to Unique so after going to several forums overseas and reading posts from guys that have used it I surmised that a starting load of 3.0gr in a 38sp under a 358140 would be well within safety bounds and was, in fact, under the min suggested loading for GM3 using this round. I did have to extrapolate a little between a 158gr and a 125gr Lead Boolit to get there.

First off, about GM3.
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It is described as a single based granulated powder. It is composed of random sized grains and is grey in color. It has an odd smell, in fact it was odd enough that I poured some out to make sure it was alright and it looked fine so I decided to begin testing with it.

I used my trusty 50th Anniversary 357 Mag Blackhawk as I always do when I start testing unknown powder as it is strong enough to take about anything on an initial loading. I used 6rds of 3 starting loads 3.0gr, 3.2gr and 3.4gr checking for pressure signs and leading. The day is 70 and sunny.

First load:
3.0gr GM3
358140 SWC
38 sp Brass
Fiocchi SPP
60/40 lube
Unsized but dropped .359 and 141-142gr average with BHN 10-10.5. The rounds were all in the black at 10 paces and showed no signs of pressure. Recoil was light as expected from the BH. Very little leading and a clean barrel. With these results showing the pressure was fine I decided to trade the BH for a SW 14-4 I just acquired and had not fired yet.

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Next was 3.2gr GM3 in the SW 14-4:

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Still little recoil but the hits were spread a little. Still a small amount of leading at the start of the rifling but the barrel was clean indicating the Bens 60/40 was doing its job.

Next was 3.4gr GM3

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Hard to believe but from 10 paces that center hole was 3 rounds. I'm not that good but this pistol appears to be. Still little leading, the barrel was crystal clean and no signs of pressure. The recoil was easy to manage and I would have no problem shooting 100rds without cleaning the gun with this load.

The brass looked like it was unfired:

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GM3 appears to be a big winner. I don't have a chrony yet it seemed to me that it was a mid range load. The felt recoil did not vary that I could tell but that is subjective. The full sized grip on this pistol kept it very manageable.

Nice recoil, no signs of pressure, very clean. What's not to like?

[texassako]

Nice write up. I am pretty excited how the A0 is working out in 357 Mag. I have a box loaded up for accuracy testing after running a bunch of loads across the chrony. There is not much out there on some of these powder, especially the shotgun powders like that GM3.

[jonp]

I found much data on 38sp here: http://www.armerialsa.it/ricarica%2038%20sp.htm

[ukrifleman]

I use GM3 powder in .357, 44-40 and 45 Colt for my lever action rifles, I have never used it for pistol loads.

I also use it for plinking loads in 6.5 and .30cal rifle rounds.


ukrifleman.

[jonp]

A little more information on GM3. I had very little leading and instead of slugging the SW as they are very well made I decided to just experiment. After fooling around I hit upon 20:1 Water Quenched (yielded about 14BHN) Sized .358. Lubed twice with Ben's 60/40 and Over 3.0gr GM3 I got zero leading with a clean bore. There was a little soot on the cases but not much. I'm going to use this result to start serious load testing.

On metering: Since I'm starting with 3.0gr I filled my Lyman 55 with GM3 and got to the 3.0gr throw. 3.0 - 3.1gr over several throws then I did 5 into the pan and it measured 15.0gr. This stuff is very consistent and pores "like water".

[BNE]

Jonp Thank you for the write up. Especially the metering information. If a powder doesn't meter well, I tend to get frustrated! I will add this to my listof powders to try. If I ever find any!

[MtGun44]

Good report, sounds like a good powder.

Glad it appears to be unrelated to Vectan SP8. Squirrelly powder. I traded into 8 lbs of it and it is
ONLY useful for 9mm Para, which seemed entirely impossible to me. However, after some careful
experimentation in .45 ACP and .44 Mag, I quit that stuff. It will load a LOT of 9mm Para at
6.5 gr per load. Works well, just doesn't DO any other cartridges. Nobel Sport ONLY lists
9mm as the "suitable for" . . . . . never heard of a powder that specific before, but it appears
to be true.

[Matmap]

Good Morning.
I am new to the forum and have come to him by my great fondness for weapons. My name is Manuel and I am Spanish.
I inherited a gun Winchester 44-40 WCF with the illusion that I have to shoot. Since 1892 is the original model, I do not want to break using existing powders.
I have seen comments that uses gunpowder ukrifleman GM3 for 44-40. I can not find tables with the powder charging for 44-40. How many grains?
Although GM3 is a modern gunpowder I read that adding Miraguano and powdered graphite can behave like black powder. It is true?
Thank you very much for your interesting to Jonp information.
Very cordial regards,
Manuel.

[captaint]

Welcome to the forum, Matmap. Great place to learn, for all of us.. I recently bought 2 pounds each of Vectan 9 something and 9.5 something. Both pistol powders. One burns close (on the chart) to Bullseye and the other burns close to Unique. They are very fine roundish granules, so it should meter really well. Wish me luck. Someone said - there's not much loading data available from Vectan on their powders. True. Going to have to take it slowly. That's OK - I'm in no hurry.

[captaint]

Just remembered. The Vectan powders are BA9 and BA9.5.

[andrew375]

I've used these two powders for many years. GM3 is a particular favourite of mine due to its easy flowing through a powder measure and clean burning. GM3 is not a Vectan (SNPE) powder but Italian, made by SNIA, a division of Nobel's explosives. In my .375 H&H 18gr. of GM3 behind a 280gr. plain base gives me .6 moa groups. Curiously this is with magnum primers, standard primers give near identical velocity readings but no where near the same accuracy.

Vectan AO should be treated with caution however! It is, as you have noted, a very promising powder but it has one very nasty flaw. When it reaches a certain load the pressure will go way over, usually at well below what the chronograph is telling you is a maximum load. For instance with .44 magnum in my M94 and the RCBS 250 grain Keith, 10 grains gets me 1250 fps (this is a from a 20" barrel) and cases are just starting to come out clean and vertualy drop out of the chamber under their own weight. !0.2 grains gives (for the two rounds I fired), 1256 fps but now the cases had to be hammered out of the chamber! I fired two rounds at this load as I thought I must have made a mistake so repeated the load tests a second time the following day.

I also tried AO in the .223 and had the same extreme occurence; curiously again with ten grains, this time under the NEI 72 gr. 9.9 gr. gave just over 1900 fps and barely enough pressure to seal the case mouth, 10 grains and the bolt locked up due to the case head extruding in to the ejector hole! Again I repeated the test with the same results. With both N320 and Bullseye best accuracy is in the region of 2200 fps with no signs of over pressure.

Naturally I had brought several kilos of the stuff so had to use it, so it gets used in my .44 magnums at 9.5 gr. Incidentally my notes show that at anything much below these loads there was considerable velocity spread, so I found there is a very narrow window where loads were safe but had an acceptable velocity e.s.

[dodgyrog]

BEWARE GM3 is hygroscopic and pressure varies as you get down the tub!

[clum553946]

jonp, have you done anymore shooting with Nobel GM3 in 38 special or other pistol calibers? Any more info on it being hygroscopic? Is it a bulky powder that works well in tall straight walled pistol calibers? (ie 38 spec, 44 spec, 45 colt?) Thnx

[jonp]

jonp, have you done anymore shooting with Nobel GM3 in 38 special or other pistol calibers? Any more info on it being hygroscopic? Is it a bulky powder that works well in tall straight walled pistol calibers? (ie 38 spec, 44 spec, 45 colt?) Thnx
Not yet. It has been on my "to do" list for sometime. I acquired several other pistols in the mean time and have been using a few different powders that I'd not gotten around to try like Titegroup. I shot some more of the 38sp and my initial impressions were about right. It is a great powder. I didn't get much time on the 45Colt but did manage a chrono (thread: I got my first chrono! I shot my first chrono!).
My next project will be to compare Hercules Unique/2400 which i found on vacation to current production Alliant Unique/2400 in my 357Mag Blackhawk.

[clum553946]

Not yet. It has been on my "to do" list for sometime. I acquired several other pistols in the mean time and have been using a few different powders that I'd not gotten around to try like Titegroup. I shot some more of the 38sp and my initial impressions were about right. It is a great powder. I didn't get much time on the 45Colt but did manage a chrono (thread: I got my first chrono! I shot my first chrono!).
My next project will be to compare Hercules Unique/2400 which i found on vacation to current production Alliant Unique/2400 in my 357Mag Blackhawk.

Thnx jonp, trying to decide if it will work for 38 spl, 44 spl, & 45 Colt cast pc bullets. I've been using 231, but the volume is so low it's hard to see if it's a low or no powder cycle. I think I read somewhere that the GM3 has good fill volume. Thnx again.

[jonp]

I found online data for all of those i think and posted links in another thread. If you cant find them pm me and ill dig them up for you

As always approach loadingd with caution. Bottom -10%

[Elkins45]

It's really bulky--that might make it a good choice for 38 special, especially in a progressive setup.

[Saltner]

The GM3 is my favorite powder handyman, the user with 357 to pierce the paper, in the 45 ACP and 7.65 Parabellum.
It works very well with the powder measures.

[Saltner]

As i said, GM3 is an excellent powder.
Test 16 shots at 25 meters with S&W 686
https://preview.ibb.co/mxErqR/IMG_20171123_140941.jpg
https://preview.ibb.co/bu0sx6/IMG_20171123_142322.jpg
https://preview.ibb.co/in8qjm/IMG_20170414_094948.jpg

Test 12 shots at 25 meters with H&K Mark 23, 200 SWC / 4.7 gn GM3
https://preview.ibb.co/jR8ZAR/IMG_20170518_150250.jpg
https://preview.ibb.co/j7YHVR/H_K_Mark_23_25_metri.jpg

Test 13 shots at 50 meters
https://preview.ibb.co/bsV34m/H_K_Mark_23_50_metri.jpg

[texassako]

Nice, I added a some to a Graf's order because it is so cheap and because of the results in this thread.