LRH Wild POI shifts and another issue

[Nomosendero]

I bought my Son a Long Range Hunter in 300WM recently from a guy who had not fired it much, a little less than a box. I think I found out why. First, I tried the remaining Hor. Precision Hunter 200 grain ammo, roughly 1.3" 3shot groups, I had some Feb Blue box 180 grain, about 2"group, then Winchester LR ammo with the 190 Long Range Accubond, about 1.25" groups. I did try a handload for my 300WM Sendero with RL25 and the 180 Accubond, that load (1 group) was sub MOA, so maybe I can get sub MOA with that or 180BT, 200Acc, 215 Berger or other bullets I have on hand.

But here are my 2 bigger concerns:
1. Going from one load to another, I have WILD POI swings even with the same bullet weights, we all see some shifts but I am talking 12-15" shifts at 100 yards, this being the horizontal shift, vertical would not vary too much with the same bullet weight.
2. I wonder if the receiver threads were not square with the receiver, as there was no way I could sight in a scope with the 20MOA P. rail I bought from EGW. Yes, I know that can happen with a scope with limited vertical adj. & I experienced that with a M700 5R 308 with a Nikon M308 scope, but I mounted a Zeiss V4 4-16 scope which has plenty of adjustment. When I took the 20 MOA base off and installed an EGW zero base I still had to use almost all of my adjustment to get the 100 yd. zero & that REALLY got my attention.

Please let me know you thoughts on this and if any have experienced this.

Thanks

[celltech]

How is the stock to barrel fit? It should be evenly spaced from the stock and not touching anything. Does the crown look damaged?

[Nomosendero]

How is the stock to barrel fit? It should be evenly spaced from the stock and not touching anything. Does the crown look damaged?
It is an Accustock, the screws are torqued well, the barrel floats fine.
I would think the crown would have more to do with poor grouping than the 2 problems I stated, it has the LRH brake which has never been removed. But, I can check.
Thanks

[Texas10]

Just a suggestion, but I've personally seen this so I'm going to pass it on to you. Remove the barreled action from the stock and look very closely at the barrel nut for any gap between the nut and action. I've had a situation where a burr under the nut produces a cocked and erratic shooting barrel. It will be slight, and you'll need a good light to backlight it to see the gap. If you do see a gap, you'll need to remove the scope rail and barrel, and hone the surface flat on the front face of the action. A new nut would be best before installing the barrel.

[Nomosendero]

Thanks TX, I would have never thought of that!

[ninner]

Every time I’ve had this happen it’s been a broken scope or loose mount.


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[Robinhood]

Set up your phone and video your sons trigger pull. My son yanked his 7 rem mag trigger so hard he missed dear every year. I videoed him and he was shocked at how hard he jerked the trigger. Now he shoots a 7mm08 and he never misses.

[Slowpoke Slim]

Every time I’ve had this happen it’s been a broken scope or loose mount.


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My first thought as well.

Loose, broken or improperly installed mounts and/or rings. And/or a broken scope. These 1 foot or better horizontal group movements, was this just (and ONLY) from switching ammo? Or were the mounts/rings/scope changed in ANY way between sessions? Is this being shot by one, and ONLY one shooter during these range sessions?

I'm wondering if it's been "too many" changes happening all at the same time, between range sessions. I'd lean back and start over again, and take a hard look at scope and mounts. Do a Box Test on your current setup, with NO OTHER changes being made.

It's easy to start chasing your tail on these things once you get caught up in the middle of it all.

[olddav]

I would also check the fit of the rail by installing only the front screws and check for a gap at the rear. If all looks right install only the rear screws and check for a gap at the front. No gap, no problem with the rail fit.
I’ve corrected this very problem by lapping the rings, installing a shim and bed the scope. This is not the easiest way but it is a very reliable.

[8mm RUM]

You don't think it is an ammo problem?
The POI shift is a normal thing in my mind, every type/brand may shoot differently.
I'm guessing your not a reloader? When we first test up a load every thing can change the poi. Powder, primer, bullet construction even when the weight is the same. Some guns will only shoot a specific load combo. May be try a different type of ammo before calling the gun a POS. Just a thought, maybe a trigger job is in store. The barrel is still new and not broke in that in its self can do it.

[ninner]

You don't think it is an ammo problem?
The POI shift is a normal thing in my mind, every type/brand may shoot differently.
I'm guessing your not a reloader? When we first test up a load every thing can change the poi. Powder, primer, bullet construction even when the weight is the same. Some guns will only shoot a specific load combo. May be try a different type of ammo before calling the gun a POS. Just a thought, maybe a trigger job is in store. The barrel is still new and not broke in that in its self can do it.



Poi is affected by ammo types but it’s mostly vertical. Barrel harmonies can lead to left-right poi changes but they are the exception not the rule. I’ve personally been reloading for 20 years and shooting for 45.


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[Slowpoke Slim]

You don't think it is an ammo problem?
The POI shift is a normal thing in my mind, every type/brand may shoot differently.
I'm guessing your not a reloader? When we first test up a load every thing can change the poi. Powder, primer, bullet construction even when the weight is the same. Some guns will only shoot a specific load combo. May be try a different type of ammo before calling the gun a POS. Just a thought, maybe a trigger job is in store. The barrel is still new and not broke in that in its self can do it.




I've been reloading since 1975. I've been loading match ammo and shooting competitively since the early 80's.

Not sure what that has to do with anything, but...

The devil is in the details. The OP has stated that changing ammo has moved his groups over a foot sideways each time he changes ammo. While different loads changing group *sizes* is pretty common, and to be expected, a gun suddenly shooting over a foot to one side just because you change a load is not. Especially if it does this each time a different load is tried (as in, not a one-off fluke). I'm thinking sights. Really nothing else in my mind can explain such a huge jump to left or right by just selecting another box of ammo.

OP,

I would start with shooting a standard Box Test with your current scope/rings/base(s) with no other change at all. Only one shooter shooting the test. Go from there.

Something is loose. I'm betting it's sights.

[shaffe48]

If the gun came with bases they often aren't screwed on well

[Nomosendero]

My first thought as well.

Loose, broken or improperly installed mounts and/or rings. And/or a broken scope. These 1 foot or better horizontal group movements, was this just (and ONLY) from switching ammo? Or were the mounts/rings/scope changed in ANY way between sessions? Is this being shot by one, and ONLY one shooter during these range sessions?

I'm wondering if it's been "too many" changes happening all at the same time, between range sessions. I'd lean back and start over again, and take a hard look at scope and mounts. Do a Box Test on your current setup, with NO OTHER changes being made.

It's easy to start chasing your tail on these things once you get caught up in the middle of it all.

I am doing the shooting & for a 300WM, it is quite mild with the brake. We can scratch that one.

[Nomosendero]

Every time I’ve had this happen it’s been a broken scope or loose mount.


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Scope is fine & as stated, I had to go from a 20MOA EGW to a zero, lateral shifts are the same.

[Nomosendero]

You don't think it is an ammo problem?
The POI shift is a normal thing in my mind, every type/brand may shoot differently.
I'm guessing your not a reloader? When we first test up a load every thing can change the poi. Powder, primer, bullet construction even when the weight is the same. Some guns will only shoot a specific load combo. May be try a different type of ammo before calling the gun a POS. Just a thought, maybe a trigger job is in store. The barrel is still new and not broke in that in its self can do it.


It appears you did not read my posts. I am a handloader, so far the best group is with a load I had worked up for my Sendero.
Thanks

[Nomosendero]

I've been reloading since 1975. I've been loading match ammo and shooting competitively since the early 80's.

Not sure what that has to do with anything, but...

The devil is in the details. The OP has stated that changing ammo has moved his groups over a foot sideways each time he changes ammo. While different loads changing group *sizes* is pretty common, and to be expected, a gun suddenly shooting over a foot to one side just because you change a load is not. Especially if it does this each time a different load is tried (as in, not a one-off fluke). I'm thinking sights. Really nothing else in my mind can explain such a huge jump to left or right by just selecting another box of ammo.

OP,

I would start with shooting a standard Box Test with your current scope/rings/base(s) with no other change at all. Only one shooter shooting the test. Go from there.

Something is loose. I'm betting it's sights.

Thanks Slowpoke Jim for a response based on experience and for actually reading my post. A box test makes sense as this is a new scope and most people think a very good scope. It is noteworthy though that if I shoot another group with the same load that I will not have that shift but still worth a look and I have a couple of other scopes to set on it too.
I also want to thank Texas Tim for something I would have never thought of.
Not all of the others but many responses responded as though they did not read my posts or have very little experience.
Thanks

[ninner]

It appears you did not read my posts. I am a handloader, so far the best group is with a load I had worked up for my Sendero.
Thanks

I’d switch scopes first and if it’s still the same I’d chuck the receiver up in a lathe and see how much runout is in the face of the receiver. Then make sure everything else is true. Even turn the barrel a little and see if your barrel has any weird harmonic issues.


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[Nomosendero]

I’d switch scopes first and if it’s still the same I’d chuck the receiver up in a lathe and see how much runout is in the face of the receiver. Then make sure everything else is true. Even turn the barrel a little and see if your barrel has any weird harmonic issues.


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Ninner, thanks. Yes, I am wondering if the barrel threads are straight with the receiver as well.

[ninner]

I chased a 300 Rum build for months that kept stringing laterally, after I gave up and got rid of the barrel. I put a 3006 barrel on the receiver and had the exact same issue. It was the dam scope I was using. Replaced the leupold with a Nikon mark 3 and now it’s a tack driver. Wish it found the problem before I sold the barrel.

Forgot to add the scope failure was recoil dependent, I have the scope on a 10)22 now and it holds zero.

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