CVA Bulllet Tumble
 

I'm gunna be deer hunting where I expect 100+ yards shots this year. I decided to try a 200 grain sabot with 150 grains of pyordex. Thought i'd be able to reach out and touch them like this. I tried to sight in my gun my shot are all over the map. I noticed at least one hit the paper sideways. Any recommendations?

Rifle type... pellets or loose... caliber...

I would cut the charge back to 100 grains from 150 and see if that does not make a difference.

CVA Stag Horn 50 caliber 1:32, using pyrodex pellets.

Well Hazel, this one ain't gonna` be easy. :s2:

Tumbling/poor accuracy could be caused by a bullet/sabot combination that's too loose in the bore.

Another possibility is that those Pyrodex pellets are moisture/humidity/age compromised.

As Cayugad said, maybe that 150 grain load is the problem. A lot (most?) guns don't shoot well with that load. If things don't improve with two pellets I would seriously consider investing in a canister of loose Pyrodex RS or Triple Seven and play with 80/90/100/110 grain loads.

Maybe your gun just does not like 200 grain bullets.

Are you shooting with a scope or iron sights? Is everything in the sight system tight. Are you shooting with a good solid rest? Are you shooting at least three shots without adjusting the sights?

See, I told you it wasn't going to be easy. :p

My first thought would be to back the powder charge down as stated. I have never gotten good, consistent accuracy using the max load of powder. You will still be able to shoot out to 100 yards and beyond using a much lighter powder load. Especially using a 200 grain bullet. I would try backing down the powder load first.

Make sure everything is consistent. If you change one little thing in your cleaning, loading, preparation, etc... it will have an effect on the bullet impact. When breaking in a new gun, I always recommend a 1 shot then full breakdown and clean routine until you know where the gun will hit out of a clean, cool and dry barrel. After that you can experiment.

How easy is the bullet loading in the gun out of a clean dry barrel?

Let us know your results.

How big was "all over the map" in group-size terms? If you bullets are truly tumbling, and you are shooting at 100 yds, you will not hit any reasonably sized backer consistently. A true tumble will give you a nice side-type profile of the bullet. It is typically not subtle.

It is relatively easy to mistake paper tearing weird on a bad backer for a tumble.

Two thoughts:
1) Not a good idea to start at 150gr, odds are it won't work out well. Especially with a light bullet.
2) 1:32 twist may be too slow. If this is the 200gr Shockwave or a similar .40cal bullet, they are long for caliber and it is possible that you need a 1:28" to stabilize them.

FWIW I had hunted for years with the 200SW at 110gr Triple Seven. And I've shot deer and ranges you probably wouldn't even think about just fine. It's all about knowing where the bullet will hit at the given range, not about a few inches of drop making a huge difference. Accuracy trumps trajectory.

Thanks for the feedback. I think i'll start by backing down the load to 100 grains of pyrodex and see what happens.

Thought about going to a 265 grain power belt but for now i try the 200 gr sabots with 100 grains of pyrodex