300yd Ladder is Revealing

[Tiny Tim]

I recently replaced the stock on my Remington 700 243 Win and converted from ADL to BDL. I rarely get to do basic load development at longer ranges. I typically just do a ladder at 100 yds and use muzzle velocities to determine nodes and max pressure, and move on from there. This time I performed the ladder at 300 yds for a Berger 95 gr HVLD and H4350. What it revealed is that as powder charges became increasingly greater, my shots strung left to right horizontally. It is a light rifle that's a bit "jumpy". I have tried working on my position and form. As I shot, I constantly ensured that as the rifle settled back on top of the bags, it came back "on target". I am right handed and I don't typically hold the forearm down, but use my left hand to manipulate the rear bag. This horizontal stringing was approx. 5". Its a cheap early 2000's ADL that never shot particularly well with the "Tupperware" stock (1-1.5 MOA), so I never would have noticed this stringing at 100 yds. The vertical shot placement was consistent with the muzzle velocities and gave me the info I needed. I originally chalked it up to the left to right wind, but it soon was apparent that it was consistently more as charge weights increased. This "error" is unnoticeable once a load is developed because zeroing places it on target. All this to ask, Is this normal? or is it poor shooting form on my part?

 

[Hondo64d]

A lot of folks talk about barrel harmonics only affecting the vertical axis, but it is not so. Harmonics affect all axis. Those effects could be exaggerated by a myriad of reasons though. Poor bedding, uneven locking lug contact or poor form being among them.

I make it a point to be able to call every shot, to know exactly where the crosshairs are, whether or not they are moving and in what direction. If they are where they are supposed to be, and not moving when the shots break, I start looking at the gun and load for issues. Having sound mechanics makes it easier to narrow things down. If you know you have a good barrel and chambering job, good bedding, good lug contact and good shooting practices then you can start focusing on your ammo.

John

 

[Tiny Tim]

Thanks John. Factory action and barrel. Has bedded scope rail w/Leopold 4.5-14 scope and Calvin Elite trigger. I'm unwilling to bed rifle at this time as I am assembling components to customize after this hunting season. With old stock, rifle shot well with reduced loads, but opened up as charges increased. Several friends have shot it over the years and all have commented that a "700 should shoot better". HS precision stock with aluminum bedding block has helped accuracy. Figured I have nothing to lose by putting it into the new stock. Have wondered if lug contact is not even. All is ultimately a moot point as the action will be trued when rebarreled and chambered. I was wondering if this was due to poor shooting form. As I said, once the load is sighted in, it holds true throughout ranges. I can typically call my shots and the rifle comes back to target after recoil. Too much shoulder, and it lands left, no enough loading, lands right. Spent about three hours firing these twenty rounds. It was an eye opener for me. At this point, the load development is more for practice in creating accurate, and consistent loads in the shortest amount of firings.