effect of rifle cant @ 200 yards

[gunlaker]

Hi,

At 200 yards, shooting .45-70, what sort of effect in MOA is rifle cant likely to have? I've got a front sight with no spirit level.

I do know that when I shoot my Shiloh with the a spirit level, what I think is vertical and what the sight tells me are often different , so I imagine I might be off by 5 degrees or so +/- with the other rifle.

thanks,

Chris.

[gunlaker]

I suppose I ought to clarify a bit.

This weekend I was continuing to work on loads for my C. Sharps 1885. I haven't managed to get the thing shooting all that well yet, but I'm seeing definite improvements.

At 200 yards I'm seeing groups under 3" high but about 6" wide. Conditions were dead calm, and visibility on the target was excellent.

I know that there are still many potential factors, but I was wondering if rifle cant could be a possible factor in these wide groups? Could I lose an inch or so due to rifle cant?

thanks,

Chris.

[Ranch 13]

I don't believe that at 200 yds canting the rifle would make that much horizontal dispersion.
Probably has more to do with fouling control, or inconsistant positioning of the rifle after each shot, or the rifle doesn't like where you're trying to rest it, or THE RIFLE THINKS the loads you're shooting just plain suck.

[Brent]

1.5 minutes tall by 3 minutes wide is does not "suck". Not even close. It might well be the norm. Most folks don't shoot as good as they think or claim anyway.

How many times did you do that and how many shots each time? A small crosswind could be the culprit, or your technique might be the culprit, but I doubt your loads are a problem.

Shoot some more. Shoot 5 more of those groups with that load and report back. I suspect you are doing fine.

[gunlaker]

I don't believe that at 200 yds canting the rifle would make that much verticle dispersion.
Probably has more to do with fouling control, or inconsistant positioning of the rifle after each shot, or the rifle doesn't like where you're trying to rest it, or the loads you're shooting just plain suck.

Yeah, the load development definitely has a ways to go for this rifle. And so does the shooters technique

I'm just trying to work through all of the possibilities. I"ve leaned a fair bit so far. Groups are getting better than they used to be, although still a fair ways behind my 1874. I'll try the same loads and compare different rest positions, wiping vs blow tubing. I have switched to SPG to rule out lube as an issue (although I haven't noticed a difference from my home made stuff yet, although I live in a cool damp climate area).

Chris.

[Ranch 13]

Chris you probably don't have the rifle settled in yet. It takes a while sometimes for things to settle down. Keep on shooting and tinkering with loads here and there. You might also want to go to 10 shot groups and see if you can get some bullets to go thru the same holes. That will tell you alot if you can get some double ups in a 10 shot string then you can figure the load is probably goodnuff, just need to work on the technique.

[gunlaker]

1.5 minutes tall by 3 minutes wide is does not "suck". Not even close. It might well be the norm. Most folks don't shoot as good as they think or claim anyway.

How many times did you do that and how many shots each time? A small crosswind could be the culprit, or your technique might be the culprit, but I doubt your loads are a problem.

Shoot some more. Shoot 5 more of those groups with that load and report back. I suspect you are doing fine.

I think I can rule out wind, but I'm no expert. The range is quite sheltered, 200 yards long, 100 wide, berms all around, and none of the trees around showed any motion.

Interestingly, the best gains I've seen so far was switching away from my RCBS mould (550gr, 20:1, .458" diameter, sorted to +/- .2 grains), to some store bought bullets (525gr Postell, hard alloy, .459" diameter, unsorted, re-lubed with SPG or my home made stuff). Those store bought bullets were certainly not nice to look at either, not consistent fillout and visible sprue tears.

When I get up to my cabin this spring, I'm going to cast some .459" bullets at 20:1 and see if bullet the improvement was bullet size, or the alloy. I'm not a very experienced caster, and get a fair number of rejects, but I can certainly do better than those store boughts .

This rifle has a very "generous" chamber, not determined by chamber cast, but by the fact that a fireformed WW case expands with an inside diameter of about .462" if I recall (my notes aren't with me right now). I'm also thinking that maybe this might make it prefer a harder alloy.

Time will tell I guess. I'll keep on trying and see where I get.

Thanks for the advice you guys keep giving. I appreciate it,

Chris.

[John Boy]

For those that believe rifle cant doesn't effect POI at any range, may want to read this test ... http://www.microlevel.biz/cant_tests.html
Somewhere in my BPCR library is a book underlined with the cant effect at 1000yds

[Dphariss]

With NO WIND, it takes very little to give 2-3" wind drift at 200 and a light breeze someplace down range could cause this and be undetectable at the firing line, wide groups are PROBABLY a holding error of some sort. OR the rifle needs to be gone over for possible problems. Loose screws, forend hard on the action. Highwalls are notorious for being loose in the stock even with tight screws. This WILL blow groups.
Canting WILL move the bullet impact and could easily make the group a few inches wider at 200.
Holding errors are a problem with BPCRs do to relatively long barrel times and fairly heavy recoil for the bullet energy. My 15 pound 45-100 is bad for this and I usually know the shot is bad from the feel of the recoil.
So be careful to hold the same every time.
This said the group you shot is not anything to be ashamed of.

Dan

[gunlaker]

Thanks Dan,

I will definitely give the screws a check right now. I do think I've solved some of my horizontal dispersion problem by playing around with how I hold the rifle. Some time after my original post I noticed that there is a big difference in horizontal dispersion depending on how tightly I pull the rifle into my shoulder. Interestingly my Shiloh seems to be less picky about how I hold it.

edit: I've also recently added a spirit level to the front sight too .

Chris.

[Kurt]

Thumbing (squeezing the thumb) or changing how deep or shallow the trigger finger is on the trigger is a big factor on horizontal strings.
Torque, letting the grip twist in your hands will give you oblique strings.
I have a stake out about 50 yards with a short thread and a goose down feather on it on calm days @ 200 yards when that feather changes a little I can see it on the target too.

Kurt

[Bozon]

I had a 45-70 load that was good, for a long time. It then went ploooieyy stinko. ???????? After a while, I figgered out my new .459 sizer was just under .458. Got out the old .459er and groups came back to good (in two rifles, a Ballard and a Sharps). For what its worth, the difference between .458 and .459 sizing in my rifles made a big difference. Also the .458 lyman bullet mould I have puts out bullets that do not shoot well in my rifles. Too bad because they cast beautifully. Other opinions will vary.