Questions about an inaccurate load

[bajabill]

I know this is a bad one, but since it is the first time I had such poor performance, I dont know if the behavior is to be expected for a bad bullet/gun combination.


44 mag, reamed to 445sm (barrel slug measures .430)

I am shooting (.430)240 rem hp, (.429)270 speer gold dot, and (.429)300 nosler hp.

For the 300 nosler, I get 7 - 10" vertical distribution at ~75 yds.  But the windage is consistent with the performance of the other bullets (1 - 2").  Is it common for this poor vertical consistency to not be accompanied by similar windage performance.  The other 2 bullets perform at roughly a 1.5 - 2 moa rifle - not great, but certainly close enough to zero the scope with.



edit, I think its a 1:38 twist.  And, I shot the same speer and nosler bullets out of my  muzzleloader (1:28 twist) with good results.

[Mitch in MI]

I wonder how the shot to shot velocity variation compares among those loads.
If the stringing is velocity induced, that would require major differences in fps.

[bajabill]

not velocity induced,     5 or 6 shot data

240s ->  2105 - 2198
270s ->  1921 - 2036
300s ->  1877 - 1936

[tykempster]

Your vertical couldn't be caused by difference in FPS, that would be on the magnitude of thousands of FPS difference.

I notice your bore is bigger than the bullets, that isn't ever good.

[Ditchdigger]

The 445 I had would shoot best with max or near max loads,the 240 went 2260 fps,the 265 hornady went 2166 fps. and the 300 gr.xtp's went 1977 fps. I was using 296 powder and the they all shot about 1 1/2" at 100 yds. My bore was .432". Of the 10 or 12  people that did the 445 conv. all said there's shot best with near max loads.   Digger

[trotterlg]

Vertical stringing , if not caused by velocity problems, is a rifle problem of some sort.  The bullet does not know up from down or left to up when it leaves the barrel, so there is some lockup or other problem going on here.  Larry

[bigvarmnt]

What scope you using? Have you used it before?

[bajabill]

that up/down vs left/right is what has me puzzled.

I had 6 rounds of each bullet, 3 targets - one for each bullet, shooting a couple of each, randomly changing from bullet to bullet so one weight did not see any noticable barrel temp different form the others.  Why would the rifle or scope know that one bullet needs to be "strung" while the other 2 do not.  Actually, my estimate of 7 -10" is low, I think one shot was at the top edge of my 15" tall backboard.  I had some good 2 shot groups, almost touching, with the 240 and 270, just could not get the 3rd one to join the party.

I think a couple of things are all falling off the bad side for the 300s,  slow twist and .429" dia.  The Noslers came in a 100 pack so it looks like I may have a lot of bullets for my muzzleloader.