Horizontal String with .375 H&H

[2000Z-71]

Had an interesting day at the range trying out various handloads in .25-06, .375 H&H and .45-70. Had a strange thing going on with my .375 H&H loads, horizontal stringing. I literally had 4 different 3 round groups that were about 6-7 inches across with less than 1 inch difference vertically across the group.

First time I've tried handloading in this caliber and rifle. Previous facorty loads I've been able to shoot groups that were 1-1/2 to 2-1/2 inches. Unfortunately I didn't have any factory ammo with me today to use as a control.

I'm just wondering if it was something in my handloads, rifle/scope or my shooting. It wouldn't really surprise me if I was flinching and pulling, I literally felt like I was having my teeth rattled at the bench.

Load was Hornady 300 grain boat tail spire points, Federal once fired cases, Federal 215 magnum primer, and 60.0, 63.4 and 66.8 grains of H4895. Rifle is a Winchester 70 Safari Express with a Nikon 1.5-6 30mm scope in Warne mounts.

I've dealt with vertical stringing before, usually a loose or improperly torque bedding screw, but never horizontal. I have no idea where to start looking for what might be the cause.

 

[2000Z-71]

Had an interesting day at the range trying out various handloads in .25-06, .375 H&H and .45-70. Had a strange thing going on with my .375 H&H loads, horizontal stringing. I literally had 4 different 3 round groups that were about 6-7 inches across with less than 1 inch difference vertically across the group.

First time I've tried handloading in this caliber and rifle. Previous facorty loads I've been able to shoot groups that were 1-1/2 to 2-1/2 inches. Unfortunately I didn't have any factory ammo with me today to use as a control.

I'm just wondering if it was something in my handloads, rifle/scope or my shooting. It wouldn't really surprise me if I was flinching and pulling, I literally felt like I was having my teeth rattled at the bench.

Load was Hornady 300 grain boat tail spire points, Federal once fired cases, Federal 215 magnum primer, and 60.0, 63.4 and 66.8 grains of H4895. Rifle is a Winchester 70 Safari Express with a Nikon 1.5-6 30mm scope in Warne mounts.

I've dealt with vertical stringing before, usually a loose or improperly torque bedding screw, but never horizontal. I have no idea where to start looking for what might be the cause.

 

[canoe on the yukon]

From reading your post,I suspect you've checked all the obvious things such as mount and ring screws and stock bolt snugness.

Without knowing more,it sounds as though you're flinching.

Over the years I've done quite a bit with heavy caliber rifles including 460 WBY,500 Jeffrey,577 Nitro express,etc.......You didn't ask but if recoil is causing problems,I may be able to suggest a few things that may help.I don't want to presume too much.Just ask if you'd like some help in that area.

I noticed you're using 4895 in the 375 H&H which is usable but a bit fast burning for that case.I would suggest you try 4350.There are other powders in it's general bulk and burning range which will do well also but 4350 is an old standby in the 375.I have gotten very good groups with the 375 using 4350.

 

[Joni_Lynn]

With horizontal grouping I'd suspect the stock (fore end).

 

[shovelwrench]

IIRC, its a load problem, one the high power guys at the range discussed. I'll check with him and try to give some more insight

 

[Guest]

A few more details would help. Such as are you using any type of bench rest and just how are you doing your shooting. Offhand from a Rest or???

Improper barrel contact against the fore end will generally cause vertical stringing while horizontal stringing is more commonly caused by either flinching or a poor or excessively heavy trigger pull. Maybe your Trigger has gotten dirty and your trigger pull has become heavier than you are used to.

 

[2000Z-71]

I'm shooting it from a rest on the bench. I was getting groups under 1" with my Ruger No. 1 in .25-06 off the same rest from it yesterday. The trigger pull issue wouldn't surprise me. The rifle is a stock 70 with a very heavy pull. I started with the Ruger first which has a relatively light trigger. I've also got rom Reloader 15 that I want to try in the .375 as well.

 

[Guest]

According to what I have read, the British "White Hunters" in Africa, used what they called a "Standing Bench Rest" for their Heavy Rifles. A .375 can be pretty brutal when fired from a normal bench rest. The "Standing Bench Rest" is pretty much just what it sounds like. You put a stool or something up on the regular bench and put your sandbags onto that. Now shoot it just like you were - just standing up instead of sitting down. It isn't as stable as putting sandbags under the fore end and also under the rear of the stock but it is certainly easier on the shooter. Besides, this is more like you'll be shooting in the field anyway.

I would also check the barrel channel for contact but like I said before; that usually causes vertical stringing. I'd also get your Trigger looked at because while it shouldn't be too light there is no reason for it to be over about four(4) pounds and it should be the same, over and over again.

 

[OKFC05]

Originally posted by Joni_Lynn:
With horizontal grouping I'd suspect the stock (fore end).

That was my first thought, having had a forend warp on me before, putting sideways pressure on the barrel that changed as the barrel warmed up.

 

[Dan Cash]

Model 70? Maybe others too. Front and middle action screw. Does it every time if it is loose.
Dan

 

[Joni_Lynn]

On the M70 that has 3 action screws it's important not to over tighten the center screw or the action may actually bend.
Does it have the recoil lug mounted on the barrel or just the one on the receiver?
Is the scope one that is known to be a good one?

 

[tdan]

A couple of possibilities here. Since you are shooting your other rifles okay, I'm thinking you are experiencing a bit of recoil aversion with the 375. I'm betting you are unconsciously gripping the stock too hard as you press the trigger. You are trying to hold it off your shoulder. Try putting a pad between the stock and your shoulder when shooting off the bench. See if this tightens things up before adjusting the action screws. You don't mention how your stock is bedded.

Since your factory loads shot better, your rifle may not like the length of your handloaded cartridge. You need to experiment with the distance of the bullet off the barrel lands to find that sweet spot for the bullet you are looking to shoot. Most reloading manuals can explain this concept.