10mm Inaccuracy. Help!

[gamestalker]

Several powders that have worked quite well for me are Longshot, Blue Dot, and 2400 did pretty well also. Of those three, Longshot has always been my first choice, with Blue Dot second, and 2400 being the #3.

As far as bullets, I don't load with lead or plated lead, so jacketed has obviously been my one and only projectile choice. XTP's & Gold Dots have both been extremely good performers, but honestly, I haven't really experienced less than stellar accuracy with just about anything jacketed.

I've never ventured beyond those 3 powders with the 10mm, but that's primarily because when it concerns handgun loads, I've always been a full house SD reloader, and Longshot is pretty darn difficult to beat for 10mm SD loads.

GS

 

[flightsimmer]

This is what I ran into, sandbag at 50ft. with a scope, Lee, hard cast lead bullets with a fairly stought load (I don't remember the FPS. velosity), 16" barrel, and it would shoot all over the paper target. So I tried some jacketed factory loads and it was a tack driver.
Maybe the rifleing is to too shallow, I don't know, but it doesn't like lead bullets.

 

[mousegun380]

Duval, ha I guess I really haven't eliminated the shooter but man I just can't imagine I'm that bad! I shoot my .44 mag well and it kicks harder than the G20. I think everyone is on the right track with Bullseye being the wrong powder for the job. I have a lot of longshot fortunately and I think I am going to work up a load with that.

Thanks to all for their suggestions! I will post results! I need to buy more projectiles....

 

[murf]

your pistol sees plated bullets as soft lead wrapped in aluminium (copper) foil. your barrel is tearing up that copper foil wrapped bullet.

ever take a sheet of foil and: wad it up in a ball, poke a hole in it with a knife, tear it with your hands, or try to unwrap it without tearing it? pretty flimsy.

go harder lead, or copper jacket if you want to run that velocity, imo.

luck,

murf

 

[readyeddy]

Accurate #7 and 9 are known to shoot well in 10mm at higher speeds with jacketed bullets. Maybe give these a try. Or factory JHP's should give you similar results.

Also, make sure your barrel to frame lockup is tight. I had a factory 40 barrel that was so loose I had similar groups.

 

[Havok7416]

I use Bullseye and Red Dot quite a bit for my 10mm loads (copper plated and coated lead 180gr bullets) and I have no problems with accuracy aside from my own occasional screw up.

 

[mousegun380]

Havok,

Out of curiosity, what is your Bullseye load for 180gr plated/lead projectile?

 

[Havok7416]

The load I settled on for regular use is extremely mild, but I did make Bullseye loads all the way up to max and shot quite a few rounds of it.

5.9gr Bullseye is what I load up normally which is listed as a starting load.

 

[dwhite]

Check your bullet diameter. I bet they are undersize. They are not sealing in the bore. I've heard of this frequently with plated bullets.

10mm and 40S&W both have a 1 in 16 rifling twist. If that load would work in a .40 it should work as well in 10mm.

I shoot 180's through my Stoeger Cougar and get very good results with 5 grains of Bullseye.

Just my two cents.

All the Best,
D. White

 

[kfox]

I would measure the bullets. I had some that measured .3995 and accuracy was very poor. Try some jacketed or lead Hy-Tec coated bullets from Missouri Bullets and look into better powders for a 10mm. Lots have already been suggested but I usually use Unique, Power Pistol, Longshot or AA#7 and they will perk the 10mm up to real power instead of 40 S&W power levels, Accuracy will also improve with better bullets.

 

[AGunNut2]

This sounds like undersize bullets and/or the barrel. See if you can borrow a Lone Wolf or other aftermarket, cut-rifled barrel. Made a big accuracy difference in my 20/21 with Extreme 180 plated flat-points my friend loads to about that speed. The polygonal rifling doesn't like some softer bullets. An alternative to try would be harder core, thicker plated 180's from RMR.

 

[Stumper]

FWIW, My initial experience with a Glock 20sf was shooting steel with factory loads-first few were on target at the ten yard gong.....then at 25 yards I was high, low, left, right. Hmm it is new gun but I shoot beter than this. On paper at 20 yards with sandbag, group was over 10 inches. Grabbed some of my handloads loaded for my Witness.... 4.5" 10 shot group.....(hardly stellar accuracy but worlds better than the first factory groups. My point is that the load may make a huge difference. I usually expect any load in any handgun to shoot better than I can offhand.....but I have found it ain't so. Sometimes the gun sucks in accuracy(NAA .22 mini revolver or Keltec PF9) and sometimes the gun can be picky-My 20SF and perhaps yours also.

 

[mousegun380]

Well you guys were all a big help with this and I thought you would like to hear the results of my work with the 10mm after the problems I had. Most of you seem to have picked out the problem correctly, it was the powder type and the charge weight I was using. I started working up a load using Longshot instead of Bullseye and once again, I am shooting straight!

I started with the following book data:

Hornady 180gr FMJ
starting 6.4gr = 950 fps
max 8.2gr = 1150 fps

Hodgdon 180gr Sierra JHP
starting 8.5gr = 1221 fps
max 9.5gr = 1287 fps

Gotta love when book data is all over the board like that... I worked up the following loads and got the resulting average velocities in a stock Glock 20 shooting 10 shot strings.

6.4gr 896 fps
6.8gr 950 fps
7.2gr 1014 fps
7.6gr 1055 fps
7.8gr 1078 fps
8.0gr 1100 fps
8.2gr 1125 fps
8.5gr 1164 fps
8.7gr 1183 fps
8.9gr 1213 fps
9.1gr 1239 fps
9.3gr 1253 fps

I shot 10 of each over the chrono and shot a second 10 out at 15 yards. I worked forwards on the chrono data going from weakest to strongest, but for the accuracy test I went backwards starting with the strongest first. I did this because I thought I would be fatigued by the recoil and I wanted the loads to get easier to shoot as I got more tired. I was right, and I stopped accuracy testing at the 7.8gr samples because I started shaking and the test would have been useless. I did the chrono testing and the accuracy testing 2 days apart.

When the dust cleared, the 8.2gr samples patterned the best. See photo. I also shot 10 factory loads at 15 yeards and they patterned the same as the 8.2gr samples.

Thanks again for everyone's time!

 

[41 Mag]

mousegun380,

Glad to see you made good progress there.

While Bullseye IS a very versatile powder sa you can see it isn't always the best in everything. Not saying that it might not shine under some cast lead loads but that is another thing altogether.

With my 10mm I worked through a few powders until I tried a couple of loads using Accurate. Again these might not be the best for every combination but man they hit the nail for mine.

As for the data spreads, you have to consider other things besides the actual weight when looking some of that over. Some bullets are built for specific uses, some have thicker jackets, some have different material for the jackets. Some have harder cores than others. Some have a longer or shorter ogive than other giving shorter or longer bearing surfaces as well. All of this comes into play when they work up their load data.

That isn't to say that one won't work with another load data, just that you have to condiser these things when your looking at several samples trying to decifer where to start from. Most if not all Sierra bullets have a solid copper jacket on them, Hornady uses a guilding metal which is an alloy and is a bit harder on most of it's bullets. I think that the cores in the XTP is of a harder alloy than some of their other standard type HP and the jackets are a bit thicker. This is why they preform so well with expansion and penetration. I do know that you will usually find their data a little different than most other HP data of similar type and wieght bullets. I cannot remember where I read it, but this was due to them being a bit heavier designed for the specific velocity ranges they performed the best in which was usually the upper end of the scale.

Anyway glad to see your load has come together and wishing you and yours the VERY BEST of Christmas Cheer.

 

[cwall64]

That is great news, it is always nice to figure out the solution!

 

[Seabeeken]

I use a 10mm barrel in my glock 21 with a 24# spring. It shoots great with accurate #7. Bullseye is too fast in a magnum class round like 10 mm. Try jacketed vice plated bullets. My glock 21 in 10mm is very accurate at 25 yds.

Ken