Recoil and accuracy

Status
Not open for further replies.
Z

z7

Member
Joined
Jan 13, 2014
Messages
1,202
It may be the wrong forum, but this is probably a good place to start.
I was working through a 308 load development recently and had great groups near starting loads with 168amax and varget and 165sierra game king and 8208. As I slowly increased powder and recoil increased I noticed the rifle was jumping up off the bench and my sights were not returning to the target area. I was at a bench using an el cheapo bipod that I was not "loading"
My groups hovered around 1.5" center to center, but I had a few that were simply a string of 5 shots 2" tall, 1/2" wide.

Does the recoil impulse play that much of a role in tiny groups? My rifle was not recoiling consistently from shot to shot, I was attempting to keep my cheek weld and trigger squeeze consistent. I'm very open to either shooter error or loads the gun didn't like, it's a RRA LR-8 predator HP, supposed to be really accurate, I've only shot hand loads in it.
 
Shooting accurately with a bipod should not be done with the bipod legs resting on a hard surface. Put some padding between the legs and the hard surface and I think you will find your accuracy improves.

Don
 
z7 said:
It may be the wrong forum, but this is probably a good place to start.
I was working through a 308 load development recently and had great groups near starting loads with 168amax and varget and 165sierra game king and 8208. As I slowly increased powder and recoil increased I noticed the rifle was jumping up off the bench and my sights were not returning to the target area. I was at a bench using an el cheapo bipod that I was not "loading"
My groups hovered around 1.5" center to center, but I had a few that were simply a string of 5 shots 2" tall, 1/2" wide.

Does the recoil impulse play that much of a role in tiny groups? My rifle was not recoiling consistently from shot to shot, I was attempting to keep my cheek weld and trigger squeeze consistent. I'm very open to either shooter error or loads the gun didn't like, it's a RRA LR-8 predator HP, supposed to be really accurate, I've only shot hand loads in it.
Click to expand...
I found the same problem as you except I was shooting off a bag. With a bipod on a hard surface (if you can't get a soft one) I've found that some 'leaning' into the bipod will help reduce this.
 
You don't mention the time between shots? You also don't mention the bench setup you are using as in exactly how the rifle is supported beyond a cheap bi pod. :) Are you supporting the butt stock or are you using a bag like a bunny bag.

The only way I can see 308 Winchester recoil having any effect is if you are not returning to the same point of aim or anticipating the recoil and the rifle going bang. In a good setup the rifle should naturally be returning to the same point of aim shot after shot. Also, the loads need to be consistent shot to shot eliminating as many variables as possible.

Does the recoil impulse play that much of a role in tiny groups? My rifle was not recoiling consistently from shot to shot, I was attempting to keep my cheek weld and trigger squeeze consistent.
Click to expand...

The recoil should be consistent for the same given loads. The 308 Winchester is not a hard recoiling rifle. For example using a 168 grain bullet, assuming about an 8 Lb rifle, having a 22" barrel, the starting load for Varget would be about 32.6 grains developing a muzzle velocity around 2100 FPS. That will yield about 10.56 ft lb of free recoil energy. The same everything with a max loading of 44 grains of Varget will get you up around 12.95 ft lb 600 FPS with a free recoil energy of around 12.95 ft lb. Even the maximum recoil energy isn't that great. While this is free recoil energy and not the felt recoil it isn't that great and the spread between minimum and maximum is < 20%.

The stringing horizontally? You are sure the rifle is consistently placed in your shoulder using equal pressure? The bounce with a hard front rest like the bi pod isn't unusual, Don covers the hard front rest well, I prefer a soft front rest off the bench. All in all it sounds like trigger pull contributing to the horizontal stringing. Trigger pull needs to be consistent shot to shot and when the rifle does go bang it should come as a surprise to you. :) There is also your breathing control along with holding and squeezing.

That's all I got with what you have provided....
Ron
 
The rifle needs to recoil the same each time if the bullet is to go where the previous one did.

As mentioned, varying shoulder pressure against the stock will cause vertical stringing in the group.

Vary where the stock is on the shoulder left to right or how you let your body move during recoil can cause the bullets impact to move left or right.

Your body position needs to be the same each time, the stocks position on your shoulder needs to be the same each time, the amount of resistance your shoulder gives to the rifle during the entire recoil sequence needs to be the same each time, and the direction you let your body recoil each time needs to be the same.

Shooting tiny groups isn't easy at first. It takes practice. :)
 
thanks to all for the responses. i do plan on next time trying to get a more comfortable setup and loading the bipod and getting some padding for the feet.

i tried to answer some of the questions in order to see if you all spot any flaws or gain give me a little more insight

"You don't mention the time between shots?"
Time between shots was 30 seconds, time between groups of loads, 2 minutes with bolt open, faster than ideal but the rifle wasn't real hot, i could put my hand on the barrel without being uncomfortable, but slowing down could not hurt.


"You also don't mention the bench setup you are using as in exactly how the rifle is supported beyond a cheap bi pod. Are you supporting the butt stock or are you using a bag like a bunny bag."
i was using a bean bag under the stock, sitting at a wooden bench.


The only way I can see 308 Winchester recoil having any effect is if you are not returning to the same point of aim or anticipating the recoil and the rifle going bang. In a good setup the rifle should naturally be returning to the same point of aim shot after shot. Also, the loads need to be consistent shot to shot eliminating as many variables as possible.
the rifle was not returning to same point or area of aim. some shots the sights would be on the target, some shots low left, high right etc. this was with the "surprise" trigger pull, and firing on the same point in my breathing cycle (end of exhale) i'm sure shoulder positioning wasn't ideal and i know i have some technique to improve.



The stringing horizontally?
I had one group string horizontally, i had 3 groups string vertically.

I know that I need to slow my cadence of firing down, and I know my technique/shoulder position needs a little work. i am saving up for a better scope/mount. the current set up is a stop gap measure and isn't comfortable to get behind (Nikon 3-9 pro-staff) and we could almost all use better trigger technique.

the main question was how much does recoil play a part. i have fired two groups with 165 sierra game king and 40.6g of 8208xbr, 5 shots each. one measured .69" outside edge to outside edge the other .75" outside to outside. i.e. all bullet holes were touching, recoil wasn't bad, the rifle was returning to the target shot to shot. same day i couldn't get 42.5-44.5 grains of varget to group better than 2" and it the rifle was jumping and not returning to a similar point of aim. 42 grains was 1.2" outside edge to outside edge. i'm not blaming the rifle, just questioning where i should focus my corrections, on me (trigger, breathing, shoulder position etc) or setup to mitigate the rifle wanting to bounce around.
thanks again
 
IMO it's very difficult to learn how to shoot well and test new handloaded ammo both at the same time. One will effect the other and you can't be sure which is doing what.

I suggest you use a known accurate load and practice your shooting technique or secure the rifle in a solid rest and test the ammo for accuracy. Once you are sure the ammo is accurate you can work on your accuracy. (which is a never ending quest IMO lol)
 
Archangel, that's my frustration, is it me or the load or the setup?
It is a fun problem though
 
fold up the legs on the bipod and shoot it off a front bag. see if that brings your groups back in line. that should tell you if the bipod is adversely affecting your shooting.

murf
 
murf said:
fold up the legs on the bipod and shoot it off a front bag. see if that brings your groups back in line. that should tell you if the bipod is adversely affecting your shooting.

murf
Click to expand...
Not a bad idea. Using a bipod well is a harder thing to do than most people think it is. (especially if it's an inexpensive bipod)
 
Status
Not open for further replies.
Back
Top