Hello,
I have ben shooting a GI 30cal Carbine for a long time,but just this Month,started using Hodgdon H110 powder.I also installed a new scope,and I'm happy as a clam with the accuracy.
I used to get an occasional sub 4 minute group;now I get some sub 2 minute groups.
However,upon closer inspection,I note that all of the "good" groups are low velocity. Charges of 14.0 grs and 14.5 grs group between inch an a half to three an a half inches;most of them in the lower range.
But a charge of 15.0 grs results in a group with a Horozontal dispersion of 2 to 3 inches and a Vertical dispersion of 4 to 6 inches.
Strangely,15.5 grs only increases the Vertical dispersion another inch.
Naturally,I'll try a load of 5.2 grs.
This is not one group. It is multiple groups in each load,over two days.
Is this normal? Would changing from a mag to a standard primer help?
I've never seen anything like this before. Any comment will be appreciated.
Frank

I'm relatively new at this reloading stuff, but the books I've read all seem to say that the best accuracy is normally found at less than maximum velocity.

Depends completely upon the rifle.

I have some that shoot anything down the barrel well, and others that prefer their own little special recipe.

Some of those are at less, velocity and others are at max our a little over max, depending sometimes upon brand of powder used also.

Switching to mag primers in not going to do much for you in my experience. However, funny thing I have noticed for accuracy in my 30/30s, that is contrary to popular opinion. Slow powders, 4350 and 4831, and large pistol primers, seem to tighten up groups dramatically. Some large pistol primers were loaded in by mistake once, but had a pleasant surprise awaiting me when the groups were the tightest this rifle has ever given. why question what works?

Frank,
get a chronograph!

If you are shooting 110 1/2 jackets, you are lucky to get the 4moa groups.

If you have a load that give you 2 moa, with a carbine, I wouldn't load anything else for it.

in reloading, you will find 2 places where a little powder ADDS alot of velocity, and what seems to be alot of powder doesn't change velocity much....

at low powder changes, the first large change means your are starting to make pressure. Unless you are VERY low on your powder charge, 90% of reloaders never find this one.

then there is the middle, and safe grounds, were a little powder adds a little velocity (pressure)

then there is the point where 1 grain makes a HUGE jump... you need to back off that load, most of the time... recoil will be more/loader.... report the same...

if one is 1: foolish enough, or 2: the barrel is pressure tested,or 3: using EXTREMELY slow powder, that person would also find that adding more and more powder gives VERY LITTLE gain in velocity.... which means that, all else being equal, you are burning powder outside the barrel, thus having no effect internally.

be safe, and shoot the accurate load. No animal knows the difference in 100fps

jeffe