.45-70 Marlin Lever - shooting reloads - is this normal?

[kenn]

I've got an 1895 guide gun that I enjoy shooting immensely. I've recently put a leupold fixed 2x scout scope on it and zeroed (or so I thought) to 50 yards. I have the following 3 loads I'm shooting:

405 grain cast lead with 12 grains unique. 1.5" groups of 10 rounds @50 yards is very easy to do and, of course, very little recoil.
340 grain cast lead with 12 grains unique. Same groups.

I've also loaded up a hornady 300gr soft point bullet (#4500) in 42 and 43gr of H4198. This is a pretty stout load - very close to federal game shok.

I've always been under the impression that significant changes in velocity would not affect left/right down range -- only height of impact due to velocity and bullet drop over distance. That doesn't seem to be the case with my 1895. With my 300gr hornady load, the zero moves to the right about 4" on a 50 yard target. I thought I might be "flinching" right, but I shot a couple dozen to be sure and it's definitely right of impact of the cowboy loads.

Does this sound normal?

[gpidaho]

Yup, Very normal in my experience. Gp

[Artful]

I've always been under the impression that significant changes in velocity would not affect left/right down range -- only height of impact due to velocity and bullet drop over distance.

What were you shooting before that gave you that impression? Any of the rifles I shoot I never assume that changing the load won't change the POI.

[kenn]

What were you shooting before that gave you that impression? Any of the rifles I shoot I never assume that changing the load won't change the POI.

I've shot many pistol and rifle reloads in cast-vs-lead and reloads-vs-factory and I know POI will change. Sorry if I implied I didn't understand that as that's a silly assumption. What I'm saying is POI of was off left-right vs. up down by a rather significant margin. At 100 yards the POI with a hot JSP vs. a milder cast lead, I'd be looking at 8-10" to the right in difference. That just seems an awful lot to me.

[dubber123]

That does seem significant, and I can't say I have ever had it happen to that degree. I have noticed it much more in handguns than rifles. I'd find it a bit annoying to have to correct windage that much.

[Flexy]

I suspect this has something to do on the side you are shooting... With my brother being left handed and when he shoots this caliber rifle, he has to adjust sideways to get the hits spot on. Just dont remember which way... :)

[flint45]

Some gun shot that way it is normal I have a 30 army krag that issuper accurate with cast boolits and soso with j-word also j-words shoot 3 inches to left at 100 yards.

[Artful]

At 100 yards the POI with a hot JSP vs. a milder cast lead, I'd be looking at 8-10" to the right in difference. That just seems an awful lot to me.

Actually not that much depending upon the changes - I have a rifle and with the same load it will shift down 12 inches and right 6 inches - just by putting a weight on the end of the Varmint weight barreled 243 WCF.

[DR Owl Creek]

...


With my 300gr hornady load, the zero moves to the right about 4" on a 50 yard target. I thought I might be "flinching" right, but I shot a couple dozen to be sure and it's definitely right of impact of the cowboy loads.

Does this sound normal?
Yes. That's normal for me too.

I have the Leupold 2x Scout Scope on my guide Gun too. I usually work up all my loads at 100 yards. When I'm loading different weight bullets for test loads, I always load some extras rounds for the first string, so I can readjust the scope, just to keep the test rounds on the right target.

Dave

[kenn]

Yes. That's normal for me too.

I have the Leupold 2x Scout Scope on my guide Gun too. I usually work up all my loads at 100 yards. When I'm loading different weight bullets for test loads, I always load some extras rounds for the first string, so I can readjust the scope, just to keep the test rounds on the right target.

Dave

Thanks, Dave. I guess I'll have to find a load I really like for the 300 gr Hornady as I haven't just yet... Once I do, I'll get it zeroed for my cast and my jacketed and just adjust windage accordingly. Elevation was almost identical between both -- at least out to the 50 yards the indoor range had to offer.

[JSnover]

I've always been under the impression that significant changes in velocity would not affect left/right down range -- only height of impact due to velocity and bullet drop over distance. That doesn't seem to be the case with my 1895. With my 300gr hornady load, the zero moves to the right about 4" on a 50 yard target. I thought I might be "flinching" right, but I shot a couple dozen to be sure and it's definitely right of impact of the cowboy loads.

Does this sound normal?
I had a Buffalo Classic that would shift 4" left at 100 yards just by switching from Darr's lube to Emmerts. Shot twenty more rounds of each just to make sure it wasn't me.

[44man]

More velocity and more spin.

[oldred]

Yes it is normal and all three of my 458 calibers do it just about as you described, you might want to check out this site for a good explanation of spin drift,

http://thearmsguide.com/5346/long-range-shooting-external-ballistics-spin-drift-13-theory-section/

[Groo]

Groo here
Sounds like your position on the bench.
The lighter loads "kick" less, causing your body to turn less to the outside.
The heaver load "kicks" more turning your body to the outside more.
This happens with pistols most often.
Try this, when you shoot , look at the front sight only.
See how much the sight moves [ to the side] with the light and heavy loads.
Move around to be more square behind the gun and shoot again.
Or, shoot from the other side and see if the impact is opposite .

[tinhorn97062]

I've also loaded up a hornady 300gr soft point bullet (#4500) in 42 and 43gr of H4198. This is a pretty stout load - very close to federal game shok



I shoot that billet over 51gr H4198. From a 22" Handi Rifle, my chrono shows an average of 2020fps.

With thag said, I've also noticed a wh sage change between various loads as well as an elevation change.

[W.R.Buchanan]

Sight your rifle in with the fastest load you will shoot and that will be your Mechanical Zero. Zero the knobs there.

Everything else will be a + elevation change, and if it requires a windage change note that too.

Always return the sight to the Mechanical Zero when done shooting, that way you know exactly where it is sighted any time you pick it up. Keep that ammo with the gun so if you need to run it is a grab and go.

Sinclair makes a really neato little book for recording your sight settings. I have a page for every load I shoot in each gun. That way I can dial in the rear sight, be it a receiver sight or scope, to the exact zero for that load. Surprisingly this works everytime.

One thing you will find is what a certain load does today it will probably do again next week.

I have been lucky that all my loads so far have only resulted in Elevation Changes.

As far as your Windage offset,,, it is probably related to the High Velocity causing the bullet to spin faster?

or maybe you are not holding your mouth right.

Randy

[oldfart1956]

Kenn sometime if the opportunity presents itself take a close look at the Buffington sight on many of the Trapdoor Springfields. Raise the ladder and look at the sides of the ladder. As you raise the rear sight in the ladder it moves not only up...it also moves left. They knew! The uprights of the ladder vary in width from bottom to top and causes the sight to do this. I found this quite profound as I didn't realize they were that advanced back at that time. I was wrong. :) They didn't do this because of any muzzle velocity change. They did it because they understood spin drift. Who knew? Audie...the Oldfart..

[TXGunNut]

Does seem a bit odd but that's why we shoot paper. I'm guessing this is a hunting rifle, if so zero it from the bench with the load you intend to hunt with. After sighting it in fire it off-hand or from whatever position you will most likely fire on game. A rifle often behaves differently in the field, we have to match our range conditions as closely to hunting conditions as we can.

[Scharfschuetze]

Not mentioned yet is the affect that an improperly applied crown on the muzzle will produce. If it is canted left or right, it seems to increase the horizontal dispersion more with higher velocities than with lower velocities. This is probably due to the gas pressure of higher velocity loads pushing on the higher side of the crown longer than the lower side.

I've had your issue with a couple of firearms and squaring the crown solved the issue. I've owned or shot a few 1895 Marlins in 45/70 and I have never noted the velocity induced horizontal dispersion you suffer, so take a look at your muzzle and see if the crown is square.

Hopefully this is the issue as it is an easy fix.

At your target range of 50 yards, spin drift will not be measurable and probably will not be a consideration until your shoot past 300 yards or further. It does come into play at longer ranges and as noted in the posts above, the old Buffington sight as well as the Springfield 1903 sight had built in compensation for the effect. The sights on the later 1903A3, M1, M14 and M16/M4 weapons did not compensate so go figure! Unless you are shooting at extended ranges though, I don't think this is your issue, but it is always interesting to consider it.

US Army testing of the 30/06 round produced a spin drift at 1,000 yards of 13" or a bit over 1 MOA, but the drift was negligible at 300 yards and barely perceptible at 500 yards. Apparently as velocity decreases the effect is more pronounced and thus more noticeable and measurable at long range. Revolutions per second (RPS) decay very slowly in relation to the over the ground velocity of the projectile.

[kenn]

Thanks all. I'll try some of the things mentioned above including the crown and see where it takes me.

[AllanD]

What you are experiencing is a phenomena akin to what a Naval Engineer would call "Turret Whip" which
describes the effect on accuracy from the laterally spaced twin guns when only one of a pair is fired in a two gun mount...

It is similar to the reason who slower velocity rounds fired from a handgun tend to shoot higher than higher velocity rounds
(slower rounds allow more time for muzzle rise in recoil)

I'm 6'3" and at my last checkup I weighed 303# and even I tend to notice stronger recoiling loads drifting further right than point of aim with increasing velocity...