Spoons01 wrote:Hi all, first post on here.
I was wondering if there's anyone out there who has had issues with the old marlin 336's with the micro groove rifling and stablizing Factory .30-30? so far i've only taken it to the range once (it's my first rifle and i can't get out to the range often), but every single round i put through it tumbled, keyholed and went all over the target at 25-50m, i put 18 rounds of Winchester SuperX 150gr HP through it as well as 5 rounds of Hornady Leverevolution 160gr FTX just to see if there was a difference. I know it's not a lot of information but hopefully someone can give me some guidence on whether this may be a simple ammo issue or something with the rifle.
My rifle is a JM stamped Marlin .336SC in .30-30 and made in 1960.
Marlin microgroove barrels from that era were noted for excellent accuracy so there must be a reason for the issues you are experiencing.
You must understand that bullet holes all over the target and keyholeing can be due to two unrelated issues especially at such a close target range.
I assume you understand what keyholing is: that is the bullet going sideways through the target.
I also assume that you have the original factory barrel with original factory stampings telling you it is 30-30 cal. and not 32 Win Special and you have tried pushing a bullet into the muzzle as others have suggested but without success.
First thing is to inspect the barrel.
Open the action until you feel the bolt reach round about the half cock position. Unscrew the lever pivot and pull it out. Pull out the lever and the bolt. Don't lose the ejector.
Clean the barrel. Look down the barrel to see if there are any "rings" or bulges.
If there are none and the rifling looks generally OK, (don't worry if there is a bit of pitting or other marks), the barrel is not the problem.
A barrel can look quite ugly and still shoot OK.
Next step is to look down and center the bore on the target by setting up the rifle securely on some form of rest but preferably in padded jaws of a solid vice. Now compare where the scope is pointing in relation to where the barrel is pointing. If the scope is pointing a long way above the target then you have your answer.
Even if you happened to have a very loose barrel or even a 32 cal barrel the bullets would be unlikely to keyhole at such a short range but accuracy would be poor.
I suspect your keyholeing could be due to ricocheting because of a badly set up scope. Understand that the scope would have to be set such that the barrel is pointing down quite a lot in relation to the line of sight.
IF that is the case then take the opportunity to rectify before reassembling but when you do remember to position the ejector in the receiver first.