Troubleshoot custom 300 weatherby reloading issues 180 hammers

willfrye027

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I am helping my uncle get his new build up and running. It’s a 300 weatherby built from the ground up by a good local smith with premium components. Topped with a new nightforce SHV F1 and nightforce rings.

He did maybe 10-12 rounds for break in and then wanted to get a load dialed in.

Shooting 180gr hammer hunters in virgin weatherby brass over RL 23, fed 215M primers.

At 77.5 and 78gr he shot three shot groups with all holes touching. Going around 3150 with 20fps ES. Very promising and typical in my experience with hammers. After some more “tinkering”, he starts to get large 2-3 in groups...so he comes back to the 78gr load and it sprays a 3in vertical dispersed group.

We checked screws and mounts nothing appears loose.

here’s the “kicker” (pun intended)...most of this shooting is being done from a Lead Sled. I hate those things and won’t use them but he likes his. My theory is that he’s losing scope zero with that much recoil into a solid wall!

Any other ideas??
 

Bravo 4

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You sound suspect of several potential issues, eliminate one variable at a time. If you suspect the sled stop using it. Then check for scope slippage, and if none put a proven scope on it. The good thing about replacing the scope is you can ensure the mounting hardware is totally secure. Without knowing what bullets were fired prior to the Hammers or how many total, I may start with a clean barrel.
 

willfrye027

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Not sure 10 to 12 rounds is enough for break in. Besides recoil was the barrel clean and cold ?
Started with a clean barrel. Cleaned every shot for the first 10 or so. I agree longer break in would be better

However he shot an awesome 3 shot group at 78gr, came back to that charge weight later and it sprayed vertical 3inches. That’s what makes me think there is something larger going on...a screw loose somewhere or maybe the scope losing zero
 

willfrye027

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Did it shoot good with new brass now it won't with fired brass? Don't discount the scope just because its a NF, ive seen one go bad.
It’s all virgin brass he’s only about 20 rounds into it.

my money is on the scope. It’s a lot of recoil slamming into that lead sled for such a heavy recoiling gun to begin with. But who knows
 

Tiny Tim

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Agree with above. Pull scope and check all fasteners, check for barrel contact with stock, check action screw torque, clean barrel to bare metal, and try different scope. A word of caution, if he insists on placing in the sled, put another of HIS scopes on it. If recoil can't be managed without a sled, brake it, and remove it for hunting if desired. Something moved/loosened if it shot well and same load went to pot.
 

Shane Lindsey

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If not the scope/bases/mount.

Twist rate? If not exactly 1-10, the 181 HH gave me issues with a 1-10.25. Do the impacts on the large groups look perfectly round?

Maybe try another bullet and see.

A few years ago I had a 270 win with 1-10 twist. I bought some of the Matrix 165gr. One day it would shoot as you describe, thinking I found the load, next outing it would not shoot- Stabilization issue. I was in California at the time also.
 

Muddyboots

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1 - lead sled telling me the recoil is not an acceptable output from this rifle for your uncle thus lead sled. How much does the rifle weigh?
2 - even with a lead sled it can be extremely difficult to square up behind any rifle to shoot "accurately" consistently. I picked one up to shoot after complete shoulder reconstruction surgery and I hated it due to inconsistency for cheek weld etc. Great to get high recoil rifle onto paper but dump it to sight in.
3 - shoot it off bags before going crazy over anything. The lead sled itself is a variable to be eliminated.
4 - since recoil seems to be a play in this, consider braking it.

Fyi - I found RL26 to be great with the 181HH out of 300WM @ 3225 and you might be able to get the velocity you want with less powder thus less recoil.
 

willfrye027

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Thanks all, this gives us a good direction to go and a few things to consider (twist) that I did not think of trying. I’ll post back up when we find the issue
 

willfrye027

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1 - lead sled telling me the recoil is not an acceptable output from this rifle for your uncle thus lead sled. How much does the rifle weigh?
2 - even with a lead sled it can be extremely difficult to square up behind any rifle to shoot "accurately" consistently. I picked one up to shoot after complete shoulder reconstruction surgery and I hated it due to inconsistency for cheek weld etc. Great to get high recoil rifle onto paper but dump it to sight in.
3 - shoot it off bags before going crazy over anything. The lead sled itself is a variable to be eliminated.
4 - since recoil seems to be a play in this, consider braking it.

Fyi - I found RL26 to be great with the 181HH out of 300WM @ 3225 and you might be able to get the velocity you want with less powder thus less recoil.
It’s a fairly light weight rifle...I’d guess around 8.5 scoped. He felt like it would be easier to find a good load with the sled which he has used many times in the past for other guns. He just likes it ha. We did some shooting off the bags as well and it’s stout but not intolerable. The sled is not a necessity at this point but I’m sure he will be sore after a long range session with it.
 

willfrye027

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If not the scope/bases/mount.

Twist rate? If not exactly 1-10, the 181 HH gave me issues with a 1-10.25. Do the impacts on the large groups look perfectly round?

Maybe try another bullet and see.

A few years ago I had a 270 win with 1-10 twist. I bought some of the Matrix 165gr. One day it would shoot as you describe, thinking I found the load, next outing it would not shoot- Stabilization issue. I was in California at the time also.
Some Impacts look round (good and bad groups), the second group at the same charge weight of a previous tiny group was pure vertical 3inches. That really gave us pause to think something is OFF
 

cantfixstupid

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I am helping my uncle get his new build up and running. It’s a 300 weatherby built from the ground up by a good local smith with premium components. Topped with a new nightforce SHV F1 and nightforce rings.

He did maybe 10-12 rounds for break in and then wanted to get a load dialed in.

Shooting 180gr hammer hunters in virgin weatherby brass over RL 23, fed 215M primers.

At 77.5 and 78gr he shot three shot groups with all holes touching. Going around 3150 with 20fps ES. Very promising and typical in my experience with hammers. After some more “tinkering”, he starts to get large 2-3 in groups...so he comes back to the 78gr load and it sprays a 3in vertical dispersed group.

We checked screws and mounts nothing appears loose.

here’s the “kicker” (pun intended)...most of this shooting is being done from a Lead Sled. I hate those things and won’t use them but he likes his. My theory is that he’s losing scope zero with that much recoil into a solid wall!

Any other ideas??
I just finished load development for my new 7 SAUM and the NF scope that I placed on the rifle did basically the same thing you describe, had it shooting .5 MOA group an hour later next group 2" group and 3" vertical from previous position. Swapped it out with a Vortex back to .5 MOA. Change the scope and send the NF to the factory for repair.
 

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