Got an old pre-safety marlin that won't shoot a consistent group to save it's life. Trying the lever-revolutions and not cleaning it up. Not looking for great but it just constantly walks around the target. I have read up on some issues with the microgroove but don't recall a good solution to it.

Any advice would be great.

Nothing wrong with Microgroove barrels in the Marlin rifles. I can shoot 1" to 1.50" groups all day long with mine, if I do my part.

Not knowing the exact model of 336 you have it's a little difficult to offer advice... the first thing that comes to mind is the barrel bands are too tight causing binding with the mag tube, or they could be a bit on the loose side as well. Forgot to ask if you are using a scope, iron sights, or peep sights, if scoped could be your mounts are just a bit loose.

Go to www.marlinowners.com and post your question, tons more experienced folks than I are on that forum and they are plenty helpful and real nice.

best of luck with your rifle.

Maybe 336W. Using a scope, weaver grand slam steel rings on leupold weaver base.

What ammo for the groups?

Check all the screws on the rings and mount to start. I have two 336s one pre-safety 336C and the other is a 2007 336W.

I reload with 150 grain sierra bullets, using 8082 XBR, have used 3031 as well but have a load dialed in for my 2007 336 with the 8082XBR that it likes, the older rifle I just aquired and have to get to the range and see what it likes. Since you mentioned trying the LeverEvolution, have you also tried anyone else's ammo in 150 grain and 170 grain?

Another item to check is the crown of your muzzle, look at it with a magnifing glass and bright light if possible and see if there are any dings, gouges or dents, those will affect the accuracy as well.

I swore by that stuff for about four years then I had problems. There are many lots of the 30-30 Leverevolution that won't group worth a damn. It was almost like the stuff was out of balance? Hornady told me "the stuff shoots better in Ballard XLRs". They claimed the microgroove was too shallow, bullcrap to me because I was getting great groups for years. I stopped shooting the Hornady all together and went to Winchester Powermax. The powermax hits very hard in every caliber.

The 30-30 Leverevolutions are the ONLY caliber I had trouble with. My 450 and 35 still do fine.

Make sure the mag tube isn't too screwed to tight.

While I don't subscribe to Devildog28's theory for that cold barrel or follow up shot, it definitely could, and has made a difference at the range. If you back it all the way out and put some lokt-tite on in, then put it back in leaving some expansion room.

A friend and I both had trouble shooting good groups with the 170 grain ammo. I picked up a box of cheap federal blue box from Walmart and immediately the groups tightened way up.

I have read other reports of inconsistency from the leverevolution. Try some different ammo.

was that box of federal 150 or 170 grain?

i have been buying that 170 grain because i'm finding it cheap at the wally world. the kind of dark brown box

guess i need to go shoot some of it

Good advice above on double checking the mechanics of your rifle. Once done, shoot the 150 grain through it and your groups will tighten right up. It is the same price as the 170 grain ammo at Walmart. I've had two different Marlin 336 rifles and have had the same good results with both using the 150 gr. blue box Federals (cheap stuff).

Yeah, sorry. I meant when I switched to the 150 grain the groups got a lot better. It should be the same price at wally world. It might only come in the red boxes now, but I think it's the same stuff that used to be in blue boxes, "federal power shock" or something like that.

well that kind of makes me wonder maybe i should have been stocking up on the 150 gr. i would thought the 30-30 would handle the 170 gr just fine.

guess there is only one way to find out for sure. gonna have to go put some lead down stream and see what works.