180 FMJ with Blue Dot

[10MilMike]

Hello 10mm fans. I just purchased my first 10mm. A glock 20 gen 3. I'm using 180 grain Montana Gold fmj with blue dot and hs6. I've read many posts here where guys really like 10.2 to 10.4 grains of blue dot for its accuracy. I've tried 9.6 up to 11 grains in .2 grain increments. 10.0 and 10.2 and 11.0 worked best from my 4.6" KKM barrel. But, the velocity is low. Is this normal with this combo of components? 10 grains gave 1042fps. 10.2 gave 1073fps. 11.0 gave 1192 fps. The data I have shows 1295fps with 11 grains BD and a 180g Gold Dot. I think Gold dots are plated though and that would change the results.
I tested 5 shot groups from about 12 yards free hand. 10.0 grains gave 1.7" groups. 10.2 grains gave a 1.4" groups with 4 shots. (One flyer) could be my fault. Total grouo size is 3". 11.0 grains gave a 2.5" group.
The hs6 worked best at 8.8 grains. 5 shots printed 1.75" at 1085 fps.

[10MilMike]

I tried my good loads again. This time from 15 yards rested. Looks like 10.2 may be the magic load. It printed a 1.25" five round group. 11.0 grains made a 3.5" group (3 touching)
I was hoping Blue Dot would give better velocity but the accuracy looks good.

[The_Shadow]

Welcome to the forum! May I ask you 10MilMike, are you hand weighing your powder charges or just dropping from a powder drop?
I hand weigh each and everyone of mine, yes it makes a difference!

I have recently started pushing many with BE-86 because of the lower flash signature!  BTW HS6 also has a low flash signature as well.

[fltbed]

Hello 10mm fans. I just purchased my first 10mm. A glock 20 gen 3. I'm using 180 grain Montana Gold fmj with blue dot and hs6. I've read many posts here where guys really like 10.2 to 10.4 grains of blue dot for its accuracy. I've tried 9.6 up to 11 grains in .2 grain increments. 10.0 and 10.2 and 11.0 worked best from my 4.6" KKM barrel. But, the velocity is low. Is this normal with this combo of components? 10 grains gave 1042fps. 10.2 gave 1073fps. 11.0 gave 1192 fps. The data I have shows 1295fps with 11 grains BD and a 180g Gold Dot. I think Gold dots are plated though and that would change the results.

Yes.  Montana Gold bullets use a harder brass jacket. (rather than the softer "gilding metal" traditionally used for bullet jackets)  They do run slightly slower than other jacketed, cast, coated or plated bullets.  In my old 40 limited gun, they ran about 5% slower compared to Bear Creek Poly/Moly coated.

You may also have a slow barrel.  I've seen 100-125fps differences in extreme cases.  That, combined with the MG bullets could account for your velocity differences.   I suggest trying some different bullets and do your own comparison tests. Please let us know the results.  I'd be interested in hearing them.

Jeff

[CtYankee]

Continuing fltbed's comment: jacketed bullets create more friction in the barrel, lead bullets less friction, and polymer coated lead even less, therefore greater velocities with lead and poly-coated. Every gun shoots differently. Minor barrel diameter differences can affect velocity without affecting accuracy, chamber diameter may affect velocity even more since you'll loose pressure expanding the case. I have two .357 Mag. revolvers, of the same barrel length. The Taurus has tighter chambers than the Ruger (to the extent that a casing fired in the Taurus won't fit in the Ruger chamber) and, at full magnum loads, the the Taurus will run about 150 fps faster than the Ruger. I would strongly suggest that you don't increase powder charges chasing some arbitrary velocity. Even though you are 100fps below your "goal" nothing you hit (especially paper and steel) will notice the difference.

[10MilMike]

Thanks guys. Good to know. I didn't know that these bullets had a hard jacket.

[10MilMike]

I am hand weighing the charges. I always hand weigh when experimenting.

Welcome to the forum! May I ask you 10MilMike, are you hand weighing your powder charges or just dropping from a powder drop?
I hand weigh each and everyone of mine, yes it makes a difference!

I have recently started pushing many with BE-86 because of the lower flash signature!  BTW HS6 also has a low flash signature as well.