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336Y grouping problem

3K views 23 replies 16 participants last post by  4dtruxguy 
#1 ·
About to throw the gun away now. Shot factory ammo , different bullet weights , no grouping at all. Reloaded with 150gr , stepping up .5 gr until max , aswell as 170gr , stepping up from min with.5 gr increments until max, no joy
Yes I can shoot, and shoot from a bench with proper support , trigger pull is fine, support gun near receiver , yes I cool barrel between shots. Loosening up the barrel bands , took away some wood on fore end , barrel not touching , crown seems to be fine.
There is a trend , out of 3 shots , there is 2 shots close , some of it less than an inch with a 3rd one always a big flyer , 4-6 inches away. Last shot not always the flyer. Hornady bullets , cci 200 and local powder Somchem S336(south Africa).
If it was not for the massive inconvenience to obtain a gun licence and waiting a year for it with a 60% chance it will be declined , then I would have sold or bashed the gun against a tree , and tried again. I spent to much money on it and have to make it work.
I worked on trigger , its breaking at 3lb , its fine. Scope 3-9x33 leupolt
Not the barrel but I need to cool down first before figuring out my next move... which I have no idea.
Think its a gun problem and not ammo
 
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#3 · (Edited)
FLOKI,
Perhaps cast bullets will work better. Gas checked pills sized to .309 or .310 might be the ticket (slugging the bore beforehand).

I was just looking at S 335 powder (somchem). Could not find S336. I was trying to find an alternative propellant.

Lever Jac's post about a scope problem is very likely. This has happened to me on more than one occaision.

Cleaning the bore every 3 shots is a technique some folks use when "breaking in" a new barrel. I personally have not
tried this since everything I have is old as the hills LOL!
 
#12 ·
You are onto something. Reminds me of a limited edition Remington 700 I purchased new in 2009 for$1000 chambered in 257 Robert's. Rifle grouped the same as the OP's. My gunsmith found a tight spot in the barrel. I sent it back to Remington and they fire lapped the barrel. It came back filthy and full of scratches. It did shoot better but velocity was 400 fps slower than my other 257 Robert's with same load. Guessing the bore was rather enlarged after they fire lapped. I hated that gun and traded it off on a Kimber and never looked back.
 
#6 ·
Any photos of the rifle? Could there be an issue with the scope? Have you tried it on other rifles successfully?



For reloads have you tried more than one type of powder? More than one type/brand of bullet? Different brass?
 
#8 ·
Floki, is the rifle new or does it have a history before you got it. I ask because I bought a mint 336cs years ago, it had been shot with cast bullets and not cleaned. It took me 2 weeks to get the lead out. The barrel steel had been stressed by bullets having to force their way down a ever narrowing bore. It would shift its POI winter to summer 4" left or right 5" high or low depending on the season this at 50yds. If you measured the barrel temperature with a digital laser thermometer (£16) to let the temperature settle back to the same level it would group 3/8 at 50 yds.

Marlin shipped a new barrel from the custom shop and it was fitted by one of the best rifle men this side of the pond (Norman Clark of Rugby). This rifle is not for sale ??.

I am in the process of posting an article hunting for a year with the 30-30.


Please keep us posted there are many here far more experienced than I who will help you. Do not give up we will get there Gar.
 
#9 ·
Hi Gareth

Its a new rifle. Done the break in of barrel by 3 shots , clean it , repeated 3 times. Also shooting for grouping after a good clean, i do shoot 2 shots to faul the barrel first. My other rifles showed that a crisp clean barrel the first shot prints differently. Got a loaner scope today , will shoot tomorrow , and continue with the proses of elimination.
Will keep you updated.
 
#10 ·
I had a 'Y' Remlin in the past....shot lights out with 150 Win lead free. I think you have gone the extra mile with the ammo....it's something else.....scope/mounts come first......then look to see if the barrel bands screws are attached firmly or are they loose? Once you have to go to the muzzle/barrel issues.....concern increases for production error.
 
#22 ·
Here is where I would start....remove the forearm, mag tube and barrel bands. Now you should just have the receiver and barrel. Put it on the bench with a sandbag under just the chamber section of the barrel. This will tell you if the problem is with something touching the barrel or not.

If its still a problem...I'd start looking at the scope mount. Double check the screws are not bottoming out in the mount holes. If not...use lock-tit (not permanent bond) on your mount screws. Put some double sided tape on the scope rings so the scope can't shift in the rings.

Other than this...ammo could still be a culprit. Maybe you don't have a very consistent lot of powder....try a different brand.

redhawk
 
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#23 ·
Welcome from Idaho & I tend to go with the scope mount being the problem, but like Redhawks suggestion too.
If it just constantly shot big groups, I'd say it was a problem with the barrel, but shooting a few rounds tight & then a couple fliers, sounds more like a scope/mount problem.
One thing that you could do is to take the scope off & shoot the irons at 50Y & see if it throws fliers then.
 
#24 ·
After reading through this entire tread it sure seems you have done everything in your power to correct the problem. I think you have a rifling or bore problem, possibly just below the crown. It sucks your in South Africa but there has got to be a excellent gun smith in that country some where. A friend had a similar problem on his 336aw and found rifle land just below the crown had a bulge of .0015 inch. found by locale gun smith. Good luck!
 
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