.357 Mag: 158gr XTP + H110 = inaccurate?

[Macchina]

I shot 30 rounds of 158 grain Hornady XTP's over 15.5 grains of H110 with magnum primers and a tight roll crimp out of my 4.2" SP101 the other weekend and was not impressed with the accuracy. I would have blamed myself, but my brother-in-law who is a very good competitive shooter had fired half of them and got the same results. There was also a significant amount of copper in the barrel.

Groups were about 4-6 inches at 8 yards. Is H110 in .357 usually inaccurate? I will normally play around with powder charges before posting something like this, but I've seen testing with H110 (in .44 magnum) that showed all charges give about the same velocity because of the go/no-go nature of the powder (can't load it light, and run out of volume around the time you hit max load). I am somewhat uncomfortable with playing around with H110 loading levels, should I feel this way?

I also have some hardcast 158 grain semi-wad cutters with wax lube in the groove. Would these be okay to shoot with hot loads of H110 (I have been loading them light with 4 grains of W231)?

 

[MtnCreek]

It's accurate for me, but I use about a grain more powder. My ruger is the DAO, so I can't really comment on accuracy so much. Smith K w/ 6" and N w/ 8" shoots very well with that combo. WSP Mag primer w/ a really full crimp.

Edit: Talking 158xtp. I have no idea about lead.

 

[Steve C]

So you "picked" a load and it is not the most accurate. This is the reason hand loaders work loads up for best accuracy.

The Hornady data I have lists 14.1grs of H110 behind a 158gr XTP as the start load 15.8grs max.

Current on line data from Hodgdon says 15.0 to start and 16.7 is maximum.

I'd load up a few (enough to test accuracy) at 14.5grs, 15.0, and 16.0 to see if you get better results from lighter or heavier load. Reality over the chrono is that even a full grain doesn't change velcoity much with H110.

There are other things that can affect the accuracy of your gun that has nothing to do with the load. Things like bad lead or copper fouling or loose sights shifting during recoil are a couple of these things.

 

[Macchina]

So you "picked" a load and it is not the most accurate. This is the reason hand loaders work loads up for best accuracy.

The Hornady data I have lists 14.1grs of H110 behind a 158gr XTP as the start load 15.8grs max.

Current on line data from Hodgdon says 15.0 to start and 16.7 is maximum.

I'd load up a few (enough to test accuracy) at 14.5grs, 15.0, and 16.0 to see if you get better results from lighter or heavier load. Reality over the chrono is that even a full grain doesn't change velcoity much with H110.

There are other things that can affect the accuracy of your gun that has nothing to do with the load. Things like bad lead or copper fouling or loose sights shifting during recoil are a couple of these things.

I looked at that same loading data and that is the reason why I choose 15.5 grains (Fits withing the .8 grains of overlap).
I have heard of stuck bullets with light H110 as well as very little difference in pressure/velocity as long as you have "enough" H110.
My question (as you helped answer) was is it safe to play around with H110 levels, or is it even worth it? I am an experienced reloaded, and play around with rifle loads a lot, however I know H110 is one of those picky powders you have to be careful with.

 

[Josh45]

Its worth trying if you like full power loads and enjoy loud booms and bright flames at night. I read somewhere a few months ago that someone carries some loads with H-110 in them. Can't recall it exactly.

I have some of it and only used it on 10 rounds because I only have 125 Gr bullets and read that light bullets and H-110 don't mix because they "Flame Cut" IIRC That was the word used. Your heavier bullets should be fine and I would play around with it some more until I found what my particular firearm liked best.

Also, Don't go below 3% start charges. You can have a bad time with that one as it states on the bottle.

 

[gamestalker]

It has been vrey accurate for me, but then again, I use a bit more stout charge than you do.
GS

 

[56hawk]

I'm starting to see a theme here as I also load 17 grains of H110 behind a 158 grain bullet and it's a very accurate load.

 

[Macchina]

Awesome guys. I'll carefully work up to some hotter loads and see what I get. I know that under-loaded H110 has extremely wide velocity ranges, I wonder if my gun is loose enough (or some other factor) that the pressure is not great enough to fully burn the H110...

 

[LTR shooter]

Is H110 in .357 usually inaccurate?

H110 has been one of the most accurate powders I've used in 357 loads. And 296. Especially in loads using the 158 XTP.

There was also a significant amount of copper in the barrel.

I would definitely clean out the copper before trying to shoot for accuracy again.

I wonder if my gun is loose enough (or some other factor) that the pressure is not great enough to fully burn the H110...

Even with my 10" TC 357 when firing loads using H110 or 296 I still see that bright "fireball" when the range dims.

 

[mnhntr]

H110 and 140gr Sierra JHC works very well for me.

 

[ljnowell]

14.5gr of 2400. No more worries. Plenty of thump.

 

[joneb]

There was also a significant amount of copper in the barrel.

Please explain, were there bits and pieces or just copper fouling ?
I have very good accuracy with AA#9 and 158gr XTPs at 13.6-13.9gr below 13gr the accuracy is mediocre.

 

[ArchAngelCD]

I have gotten very good accuracy from several different bullets and W296. My best charge weights fall between 15.8gr and 16.4gr with 158gr bullets. I suggest your charge weight is the problem, not the powder. I see no reason not to treat this powder as any other and try to fine the load which is accurate in your revolver.

 

[USSR]

The most accurate load I have found with the 158gr XTP bullets is, 16.0gr of 4227 with a standard primer.

Don

 

[4895]

I believe the "flame-cutting" issue in .357 mag is from 110 grain bullets and 296/H110 mag loads. 125 grains seem to be fine with my mags.