Front base screw interference with action threads.Source of my problems??

Kelly Timoffee

Kelly Timoffee

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I may have found the reason for my woes on my current load development extravaganza.

How much of a factor do you think these two items would be?

Front base front screw...

Lovely thread imprints.





I also noticed the front action screw hole on the bottom metal being more rearward than the actual hole of the action.I corrected the fit of the bottom metal as much as I could.Ignore the left/right alignment as I was move to get the best photo possible, left and right it is centered.



Hopefully the end of it, I am not switching scoped just yet until after I try again with these corrections.
 
Seldom do the action bolts line up with the bottom metal. I find it all the time when glassing actions. I use long headless bolts and mill the recoil lug recess slightly. Have the bottom metal taped in place. Remove the trigger assy... drop the action in... until you mill the recoil lug recess a little it wont drop in... I wrap masking tape around the barrel close to the end of the forearm to center the barrel. Glass the action this way with no stress...

The front mount screw would not be holding the base down properly and that can affect accuracy.
 
shave a thread off the base screw and reinstall. that should remove your binding and base wiggle which will help with accuracy or consistency
 
So, for the experts, can this be an indication of anything?

There always has been a visible warble near the muzzle about 3/4" back.

Put a strait edge on it and it does show.It is an Olfa blade and a flash light behind to show the low spot.It does appear to go around the circumference.


 
Well - I think you need to address the offset in the front action screw. Having the action bedded stress free in the stock is fundamental to accuracy, as I have proved to myself many times.
 
cosmic said:
Well - I think you need to address the offset in the front action screw. Having the action bedded stress free in the stock is fundamental to accuracy, as I have proved to myself many times.
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Took care of that already, opened up the stock hole and the bottom metal.

I changed optics, went out with more test loads , even tried some factory ammo, no change.

I think everything has been done to this thing that can.The smith went through it when he did the new barrel.All he added was a rear pillar at the time and opened up the stock a bit for the slightly large barrel contour.

I am at a complete loss and will send it out to someone and pay for them to go through it and shoot it.
 
If there is a machine shop in your area ask if they will stick a pin gauge down the bore. See if that low spot on the outside of the barrel is also in the bore. I doubt it, but you never know. If it is, chop an inch off the barrel and recrown.
 
If your barrel has been button rifled there may be a possible explanation here...

https://www.rifleshootermag.com/editorial/gunsmithing_rsgunsmith1/83442

"Moreover, we've tapered it so that the barrel's much thicker at the rear than at the muzzle. It's not hard to imagine, then, that when all that surrounding metal is machined away to form, say, a lightweight sporter contour having a .550-inch muzzle diameter, there's a tendency for the bore to "bell" the closer it gets to the muzzle, because the steel's resistance to latent expansion stress from the button having passed through is now diminished."

apparently this can also happen after a button rifled barrel has been shortened and re-crowned.
 
AP said:
If your barrel has been button rifled there may be a possible explanation here...

https://www.rifleshootermag.com/editorial/gunsmithing_rsgunsmith1/83442

"Moreover, we've tapered it so that the barrel's much thicker at the rear than at the muzzle. It's not hard to imagine, then, that when all that surrounding metal is machined away to form, say, a lightweight sporter contour having a .550-inch muzzle diameter, there's a tendency for the bore to "bell" the closer it gets to the muzzle, because the steel's resistance to latent expansion stress from the button having passed through is now diminished."

apparently this can also happen after a button rifled barrel has been shortened and re-crowned.
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That makes a whole lotta sense.Thank you for that.

So it's gotta be rifled before cutting the contour.

As yes it is a light weight barrel.

I'll have to find out what process Benchmark uses.
 
If that is a Benchmark barrel I wouldn't bother looking to blame it. I have turned top quality button rifled barrels down from a heavy barrel to pencil thin and they shot just fine.

How long a throat does it have? What cartridge and action? What does the crown look like? How badly does it shoot? Does it shoot better with factory ammo? Maybe re-bed it and make sure it is stress free with clearance on the front, sides and bottom of the recoil lug and clearance in the action screw holes. Try a different scope? Clean the barrel?
 
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guntech said:
If that is a Benchmark barrel I wouldn't bother looking to blame it. I have turned top quality button rifled barrels down from a heavy barrel to pencil thin and they shot just fine.

How long a throat does it have? What cartridge and action? What does the crown look like? How badly does it shoot? Does it shoot better with factory ammo? Maybe re-bed it and make sure it is stress free with clearance on the front, sides and bottom of the recoil lug and clearance in the action screw holes. Try a different scope? Clean the barrel?
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I've done pretty much everything you stated.

I have a thread on it that covers most of what you just asked but I will answer what isn't in the thread.

https://www.canadiangunnutz.com/for...der-test-vs-ladder-test-FAIL-Rifle-needs-help

Craige Douglas cut it to 3.550" with LRAB 190gr. I did my testing at 0.010" jump after a seating depth test.

It is a 300WM in a Vanguard action.

-Crown photos or in other thread.

-Shooting results in other thread with factory ammo , I've shot 3 bullets and three powders out of it.Factory Gold Metal Match at 250 was a horrible 5 shot group.

-I bedded it , opened up the stock.Craige opened it up more with the new barrel, installed a rear pillar and the barrel, went through rifle and I received it back.

-Tried a different scope on the weekend.

-Barrel was cleaned frequently at start during break in procedure, then roughly every 50-70 shots after.Cleaned very easily after a few range trips.

It did shoot one time good groups with 190LRAB at 100 yards at 0.010" jump, but could never duplicate a decent group after that.This was only 6 shots.

The ONLY thing that is different from what you states in the clearance at front sides and bottom of the recoil lug.I bedded it in nice snug so there was no movement in any direction.Is that not the normal way of bedding it? Craige did look this over , could this be a major issue?

I'm willing to pay to have someone to go through this rife because as it sits I have a $1700.00 rifle that is 2-4 MOA with a Benchmark barrel.

If you would like to be of assistance I'll make it worth your time.

One thing I didn't like is my bedding compound turned a funky color when it cured but it did set up solid.It was an acraglass kit.
 
The test I would give it is a 180 gr flatbase Sierra bullet behind a max load of RL 22. If it doesn't group an inch or so, tear the barrel off and send it back to benchmark. Lemons happen. I've heard of another benchmark that didn't shoot and they replaced it.
 
A tight lug in bedding is not necessarily the problem. It can be a potential problem. It is harder to seat fully after taking it out of the stock... and bedding can scrape off and build up under the lug. If it has clearance on the front, sides and bottom you never have to worry about it... I have never had a fully bedded lug shoot any better than one with clearance.

At this stage I would contact Benchmark. Several years ago I had one match select barrel from Shilen that did not perform and Ed replaced it. I had a Hart barrel that didn't perform and Hart didn't do a thing about it. Stopped using Hart barrels many years ago. My guess is Benchmark will stand up. Talk to them nicely and explain what's what.
 
guntech said:
A tight lug in bedding is not necessarily the problem. It can be a potential problem. It is harder to seat fully after taking it out of the stock... and bedding can scrape off and build up under the lug. If it has clearance on the front, sides and bottom you never have to worry about it... I have never had a fully bedded lug shoot any better than one with clearance.

At this stage I would contact Benchmark. Several years ago I had one match select barrel from Shilen that did not perform and Ed replaced it. I had a Hart barrel that didn't perform and Hart didn't do a thing about it. Stopped using Hart barrels many years ago. My guess is Benchmark will stand up. Talk to them nicely and explain what's what.
Click to expand...

Is there anything I could of buggered up to cause this type of grief? I am always being diligent and careful and thorough with all my work and rifles.
 
guntech said:
A tight lug in bedding is not necessarily the problem. It can be a potential problem. It is harder to seat fully after taking it out of the stock... and bedding can scrape off and build up under the lug. If it has clearance on the front, sides and bottom you never have to worry about it... I have never had a fully bedded lug shoot any better than one with clearance.

At this stage I would contact Benchmark. Several years ago I had one match select barrel from Shilen that did not perform and Ed replaced it. I had a Hart barrel that didn't perform and Hart didn't do a thing about it. Stopped using Hart barrels many years ago. My guess is Benchmark will stand up. Talk to them nicely and explain what's what.
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Just talked to Courtney at Benchmark, more than awesome to deal with, she will contact Gary and see how we want to proceed.

And like I always do, I start by saying I need help and am not there to bash product and say I usually blame myself first.
 
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