Inconsistent POI.

blacklab1

blacklab1

Sergeant of the Hide
Full Member
Minuteman
Sep 23, 2018
195
145
#1
I put a new rifle together for deer season this year and I’m less than impressed with it. Parts used:
C A Ridgeline 308 with 20” carbon barrel
McMillan HTG stock
A G - M5 bottom metal
TT trigger set at 2.5lbs
EEW 20 moa base
Vortex PMR rings
Leupold VX-5 3-15 x 44
Hornady 165gr sst
The action started out torqued to 35, 45 and then 55 in lbs, rings and base are torqued to spec. I’ll do 3 shot groups @ 100 yards with about 20 minutes in between to let it cool down and the POI will shift from group to group. I put my Mark-5 on it to see if I had a dud scope but I get the same results. Today it started out right and shifted left by the end of the day. I accept the fact that it’s a factory barreled action and will only shoot 1.25 MOA but why is it shifting? (Disregard the 3 shots in the middle of the paper, they were from a different rifle)
 

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#2
Torque to 65 in-lbs on the action screws and see if that helps. That's what I torque all my aluminum bedded (and chassis stocks) actions to.

If you bough the barreled action from @christensenarms then maybe you can send it in and have them look at it. I had that issue with an MPR 6mm ARC, and they ended up having to build an entirely new rifle (action and all) from scratch to send back to me.
 
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#4
Try different ammo as mentioned above.

l took my competition rifle with me to Tennessee last summer and shot at Dead Zero Shooting Park. It was grouping sub 1/2 minute with my hand loads.
I ran out of my hand loads and bought 2 boxes of FGMM and it was grouping between 1 -1.75 moa.
Switched ammo and went to 0.5-0.7 moa.

Is it possible that the recoil lug isn’t well seated up against the stock?
 
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#6
Thump_rrr said:
Try different ammo as mentioned above.

l took my competition rifle with me to Tennessee last summer and shot at Dead Zero Shooting Park. It was grouping sub 1/2 minute with my hand loads.
I ran out of my hand loads and bought 2 boxes of FGMM and it was grouping between 1 -1.75 moa.
Switched ammo and went to 0.5-0.7 moa.

Is it possible that the recoil lug isn’t well seated up against the stock?
Click to expand...
Yes it’s very possible the recoil lug isn’t seated against the stock. McMillan said their stocks don’t need to be bedded so I just torqued it down. I guess that’s my next step.
 
#7
Looking at those groups mate it looks like inconsistent shoulder index is actually the problem.

When you shoot your groups, you're alignment is X. You finish your group and reset your position but you reset the butt in the shoulder Y, which is causing the consistent shift in the group.

The lateral stringing in your groups is not seating the butt against the shoulder properly/consistently which is allowing it to slip under recoil. You run the bolt and the gun shifts just that little bit and over it goes. Right handed shooters they tend to string left.

This is a REALLY common issue I see during instruction. I had these EXACT same looking groups when I went over to an MRAD and the Desert Tech because I couldn't change the length of pull to what I was used to, so these groups are etched in my mind.

Square your shoulders bud. Don't try to "blade off" or put your body on an angle. I know it's tempting, especially shooting off a bench. Feel where that stock is sitting both in the X and Y planes against the shoulder and try to get a rhythm with it.

Sick looking rig mate, you'll get there.
 
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#8
blacklab1 said:
Yes it’s very possible the recoil lug isn’t seated against the stock. McMillan said their stocks don’t need to be bedded so I just torqued it down. I guess that’s my next step.
Click to expand...
You can try loosening the action screws and while holding the rifle with the barrel pointing up tap the butt of the rifle on the ground then tighten the action screws with the rifle still in a vertical orientation.
 
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#9
Zigjib said:
Looking at those groups mate it looks like inconsistent shoulder index is actually the problem.

When you shoot your groups, you're alignment is X. You finish your group and reset your position but you reset the butt in the shoulder Y, which is causing the consistent shift in the group.

The lateral stringing in your groups is not seating the butt against the shoulder properly/consistently which is allowing it to slip under recoil. You run the bolt and the gun shifts just that little bit and over it goes. Right handed shooters they tend to string left.

This is a REALLY common issue I see during instruction. I had these EXACT same looking groups when I went over to an MRAD and the Desert Tech because I couldn't change the length of pull to what I was used to, so these groups are etched in my mind.

Square your shoulders bud. Don't try to "blade off" or put your body on an angle. I know it's tempting, especially shooting off a bench. Feel where that stock is sitting both in the X and Y planes against the shoulder and try to get a rhythm with it.

Sick looking rig mate, you'll get there.
Click to expand...
Thanks for the input, to be honest I never really paid attention to how the stock was sitting on my shoulder.......I honestly didn't know it was that important. I have a few chassis rifles that I never noticed a POI change like that, but thinking about it, I took a lot of time setting them up to fit me to where I'm perfectly comfortable so hitting the same pocket (Y) is probably something that I don't need to concentrate on a whole lot. I was never really that picky with hunting rifle accuracy until I started to dabble in this long-range stuff, now I'm completely anal about it.

Thanks bud, I owe you one.
 
#11
blacklab1 said:
Thanks for the input, to be honest I never really paid attention to how the stock was sitting on my shoulder.......I honestly didn't know it was that important. I have a few chassis rifles that I never noticed a POI change like that, but thinking about it, I took a lot of time setting them up to fit me to where I'm perfectly comfortable so hitting the same pocket (Y) is probably something that I don't need to concentrate on a whole lot. I was never really that picky with hunting rifle accuracy until I started to dabble in this long-range stuff, now I'm completely anal about it.

Thanks bud, I owe you one.
Click to expand...
No worries;

Keep us posted. Always good to see people succeeding and growing and learning.

Love that rifle too. Looks great. MORE PICS
 
#12
Light weight or ultra light weight rifles demand perfect fundamentals, laziness you get away with on your comp rigs won’t work for LW/UL rigs. It’s not that you suck, it’s just a different ball game. I practice dot drills with mine, build position, fire one, break position, repeat. Don’t do it for time at first, practice perfect fundamentals with each shot. Shoulders square to the target, solid npa, reticle focus, breathing, etc.. Keep at it, you’ll see things tighten up.

Awesome rig btw!

IMG_2899.jpeg
 
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#13
Zigjib said:
No worries;

Keep us posted. Always good to see people succeeding and growing and learning.

Love that rifle too. Looks great. MORE PICS
Click to expand...
That’s actually 1 of 2 rifles put together for this season. I just picked up the other one from the smith today after getting headspace. The 2nd one is an Aero Solus with a Proof 20” 6.5 Creedmoor. Hoping to get out this weekend to try it.
 

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#15
blacklab1 said:
That’s actually 1 of 2 rifles put together for this season. I just picked up the other one from the smith today after getting headspace. The 2nd one is an Aero Solus with a Proof 20” 6.5 Creedmoor. Hoping to get out this weekend to try it.
Click to expand...
They look great mate. That classic stock is still 110% in aesthetics
 
#16
Zigjib said:
Looking at those groups mate it looks like inconsistent shoulder index is actually the problem.

When you shoot your groups, you're alignment is X. You finish your group and reset your position but you reset the butt in the shoulder Y, which is causing the consistent shift in the group.

The lateral stringing in your groups is not seating the butt against the shoulder properly/consistently which is allowing it to slip under recoil. You run the bolt and the gun shifts just that little bit and over it goes. Right handed shooters they tend to string left.

This is a REALLY common issue I see during instruction. I had these EXACT same looking groups when I went over to an MRAD and the Desert Tech because I couldn't change the length of pull to what I was used to, so these groups are etched in my mind.

Square your shoulders bud. Don't try to "blade off" or put your body on an angle. I know it's tempting, especially shooting off a bench. Feel where that stock is sitting both in the X and Y planes against the shoulder and try to get a rhythm with it.

Sick looking rig mate, you'll get there.
Click to expand...
Yep. It can be hard to get repeatable results of a bench. Especially when you wait 20 minutes and get up or move around then go back to the rifle. This is my nemesis especially doing load development with OCW shot round robin. In addition to feeling where the rifle is in your shoulder pay close attention to how the rifle recoils. It's very likely that the movement is different on recoil for the differing groups.
 
#18
blacklab1 said:
Yes it’s very possible the recoil lug isn’t seated against the stock. McMillan said their stocks don’t need to be bedded so I just torqued it down. I guess that’s my next step.
Click to expand...
Some of their stocks don't need bedding.
I looked up the M40A1 and it doesn't specify one way or the other.

When looking at POI shifts like that I go to bedding, or something loose- action screws, scope mount/rings, or possibly the scope itself (swap out with a known "good" one to rule that out). With a properly stress-free bedded receiver I've found action screw torque wouldn't have such a significant effect on groups like that. JMO
 
#19
Zigjib said:
Looking at those groups mate it looks like inconsistent shoulder index is actually the problem.

When you shoot your groups, you're alignment is X. You finish your group and reset your position but you reset the butt in the shoulder Y, which is causing the consistent shift in the group.

The lateral stringing in your groups is not seating the butt against the shoulder properly/consistently which is allowing it to slip under recoil. You run the bolt and the gun shifts just that little bit and over it goes. Right handed shooters they tend to string left.

This is a REALLY common issue I see during instruction. I had these EXACT same looking groups when I went over to an MRAD and the Desert Tech because I couldn't change the length of pull to what I was used to, so these groups are etched in my mind.

Square your shoulders bud. Don't try to "blade off" or put your body on an angle. I know it's tempting, especially shooting off a bench. Feel where that stock is sitting both in the X and Y planes against the shoulder and try to get a rhythm with it.

Sick looking rig mate, you'll get there.
Click to expand...
This can't be stressed enough. Have to do the *exact-same-thing* every time. Entire groups shifting in POI is almost definitely not the rifles fault.
 
#20
3rdfocal said:
This can't be stressed enough. Have to do the *exact-same-thing* every time. Entire groups shifting in POI is almost definitely not the rifles fault.
Click to expand...
I retract my prior statement after taking a better look at the targets :)
I agree. Group sizes aren't substantially different, something "loose" is usually inconsistent scattergun groups.
 
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#21
3rdfocal said:
This can't be stressed enough. Have to do the *exact-same-thing* every time. Entire groups shifting in POI is almost definitely not the rifles fault.
Click to expand...
I’m leaning toward operator error. This rifle weighs about half as much as my Zeus, and I spent countless hours getting the chassis set right on that one. I didn’t realize how much a lighter/configured different rifle amplifies poor fundamentals.
 
#22
blacklab1 said:
I’m leaning toward operator error. This rifle weighs about half as much as my Zeus, and I spent countless hours getting the chassis set right on that one. I didn’t realize how much a lighter/configured different rifle amplifies poor fundamentals.
Click to expand...
I've struggled to shoot super light rifles consistently, the ergonomics usually suck and they're not usually guns that you spend a lot of time shooting. I suck it up and hunt with a heavier rifle that I shoot very often and have a lot of confidence in. Ergonomics and fundamentals are the last thing I'm thinking about when there's a narrow window to take a shot, the muscle memory is there or it isn't!
 
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