recoil affecting accuracy

[JamieD]

I have a 375 RUM that will group under 1/2 inch at 100 yards off the bench out of a led sled. I took it to a 400 yard range and it would group under 4 inches off the roof of my pickup but it was 9 inches lower then I thought it should be.

When I got home I shot it off the bench again and it was right on. I thought this was odd so I shot it off the bench holding it and I was 4 inches low, so I tried it off my sticks and it went in the same hole as out off the sled. Then I shot it off hand a few times and had a 3 inch group 1 to 4 inches low.

I talked to the smith that built the gun and he and I think that when the gun is solid the muzzle rises before the bullet leaves the muzzle then off hand it can come back thus hitting lower.

I was wandering if anyone has a solution to this I really do not like breaks as I do not want to hurt anyone hearing.

I am trying to think of a way to hold the rifle more consistent for hunting or weighing the rifle down a bit to reduce muzzle jump. I do not no if they port rifles and if so if that would help muzzle jump without increasing noise.

Any insight would be helpful.

 

[PHOENIX PHIL]

Weight and/or a mercury recoil reducer would be my first suggestion. What do you have for a recoil pad? Pachmayr Decelerator and Limsavers are my preferred and help greatly. I'd also recommend using the so called sissy pads, the PAST version works well.

Read about them here: Past Recoil Pads

Over the last couple of years my shooting has increased greatly. With adding a .375H&H and a .416 Rigby to the arsenal so have the heavy hitters. I have a lead sled, but to be honest I've moved away from it. I still use a mechanical rest at the range but it is very basic. I've really become conscious of how I set up the rest. I make sure that when I'm lined up, the butt of the rifle is square on my shoulder and I'm not leaning over. By leaning over the butt is not square to my shoulder and is more on the top edge if you can imagine what I'm saying. This concentrates the force of the recoil into a smaller space thus increasing the pain.

Between being careful of how I'm lined up and using the PAST pad, the .375 and my .300 Win Mag are just a second thought. The .416 Rigby is still a wake up call everytime I shoot it, but not that bad either.

 

[BRICKBURN]

First thought that comes to mind is whether you are holding the rifle the same way. Fore end grip.
Off hand are you holding it tighter??

 

[Norwegianwoods]

I never rest the gun directly on a hard surface for this reason.
Very often will the gun jump up then, making your POI go higher. I always hold my hand between the hard surface and the stock. This is because your hand acts like a sponge, dampening the force between the gun and the hard surface. If the hand or something else dampening the force is not there, then the gun will jump up from the hard surface.
How much depends on how hard and fast the recoil is and if the barrel is totally free floating or not.

I think your smith is half right The gun comes up from the hard surface, making it hit higher. But when off hand, the gun doesn't come up because your hand dampens(stops) the force from going down into the surface and back up again into the stock.


A 300 win mag with a pressure point in a light stock, a member at the shooting club owned, was a totally nightmare when it came to this.
When he rested the front end of the stock directly in a metal rest standing on concrete, he would hit almost 8 inches higher at 100 meters than he did when he held his hand between the stock and the rest.

I have tested this out with many of my guns and with different kinds of rests and I have learned that some of them I will never put a bipod on as the POI is to different using the bipod or not. When using sticks, I always have my hand between the sticks and the stock.

I am rather sure this is the reason for why you experience the change of POI.
It can help to totally free float the barrel if it is not already.
The best solution in my opinion is to either always shoot the gun with the same type of support/rest and always use it the same way.
Or you must hold the front end of the stock with your hand and have it between the support/rest if you use a solid support/rest.

I use the latter as it works in all situations. With or without a rest.

 

[Nyati]

Which of the Past Recoil Pads are you using, Phil ?

 

[PHOENIX PHIL]

Which of the Past Recoil Pads are you using, Phil ?

If you click on the link in my post above, there's a picture of 4 of them, the bottom one that is kind "J" shaped is the one I use. I can't remember the thickness, perhaps a 1/4 inch?

When shooting the .416 off sticks or off hand, it really takes that edge off. On the bench, well it's still a .416 Rigby, but it helps get you through several rounds for load development or sighting in.

 

[Nyati]

If you click on the link in my post above, there's a picture of 4 of them, the bottom one that is kind "J" shaped is the one I use. I can't remember the thickness, perhaps a 1/4 inch?

When shooting the .416 off sticks or off hand, it really takes that edge off. On the bench, well it's still a .416 Rigby, but it helps get you through several rounds for load development or sighting in.

Thanks Phil, it is 1/4 inch thick, the Field Shield.

Last week I ordered a Mag Shield, 1/2 inch, for shooting off the bench, as I have a problem with my shoulder, and need some protection.

 

[Diamondhitch]

I have a shooting machine that I use when working up loads, it shows how well each load is but is of no use for sight in as it consistantly groups much lower than off of a regular rest or bipod. I also notice slight shanges in POI with my .338 Lapua depending on where the stock sits on my shoulder.

Why not go back to 100yds and try shooting just like you did at 400?

The other culprit, although 9" seems extreme, is claimed BC/velocity and calculated ballistics. Always confirm your gun at each range to determine a true trajectory for each bullet and load before trying any long range shots at game.

 

[JamieD]

Thanks guys!!!!!

I would have never guessed that you could shoot good groups and then change poi that much with a different hold.

Norwegianwood if you lived closer I would take you out for steaks. I've been fighting this problem for 2 years. I always hit low off hand. I thought I was flinching. After I adjusted my zero with something soft under the gun and only me behind the rifle (no lead sled). I shot off hand and hit on the money. I went to where I have a 400 yard target set up and was on the money again.

When I was trying to set up a rest without the sled I ended up with a shot bag under the stock, I turned it a little so I could get at the trigger. My group moved 3 inches to the right. being more educated now I put a pair of gloves on the bag and the group went back to center. The bag being crooked turned the gun in recoil.

I built a 375 RUM 3 years ago and it shot well but was quit heavy. My ph poked at me about this (it looked like I has carrying a varmint rifle). I wanted to build a second one any way so I made it light (fluted barrel, MPI light stock, stiller action, aluminum base and rings). It shoots great .2-.5 inch but poi would move. now I know why.

If I build another it will be at least a pound or pound and a half heaver. Then I may not have this issue.

I got to say it is fun to have a mountain rifle that will shoot a 350 gr. 375 bullet 2750.

Thanks again !!! This is a load of my mind. I am 28 days from leaving, and my gun was driving me nuts.

 

[BRICKBURN]

Thanks guys!!!!!

I would have never guessed that you could shoot good groups and then change poi that much with a different hold.
.....

In competitions a friend just changes his grip: graduating from holding the front end down hard to an open palm and it definitely changes POI. All learned in the days before he could afford an adjustable scope.

Glad you are more relaxed for your hunt.

 

[Norwegianwoods]

Glad to help and good to see that you are all ready and confident for your hunt
Take lots of photos and write us a report of it all.