Marlin 336 Scratches Brass.....

[Adobe Walls]

Howdy.

I am in need of some advice as to the likely trouble spots inside my 336.
Last year I bought a late 70's vintage 336 in .35 Rem. and haven't really had the opportunity to wring it out completely just yet. As these things go, I've got a bit less than two weeks left to get it woods ready for deer season. I zeroed it last year with a Williams 5D peep and 200 grain factory CoreLokts. Accuracy was so-so but adequate at the 100 yard mark. I determined to try and pull it together with a new scope and some Warne QD rings and bases for this season. I'm sure that the accuracy with a scope will show improvement over the peep sight, and I'll be better able to tweak screw tension on the barrel bands and mag tube plug screw etc. and have a better chance of seeing the difference on the target. The biggest aggravation to me is the longitudinal scratches that this rifle likes to impart to new brass. Given the price of components these days I hope to get maximum reload life out of the brass while I tune this rifle. I have crocus cloth, cratex bobs, emery paper and even wet/dry sandpaper as well as dowel rods to use for mandrels to polish the inside of the rifle. I'd just like to hear from someone that has done this before and has a good clue as to where to start looking for the offending trouble spots.AW

[Hobie]

Well, #1 I wouldn't touch a thing until I KNEW what was scratching the brass where. I recommend inserting an UNSCRATCHED case with the headstamp in the vertical top-to-bottom orientation directly in the chamber. Extract the case. If there are NO scratches this must be on the carrier or next most likely at the juncture of the magazine tube and the receiver. Verify by loading two such cases also so orientated into the magazine and running them through the action. This should tell you where to look for a burr (and it is likely one very slightly burred part). I would remove ONLY that burr. I am a STRONG proponent of the dictum, "if it works don't fix it."

[PaperPatch]

Adobe,

I had the same issue on my 444 Marlin. The culprit was a spur-like burr on the INSIDE of the loading gate. The gate was easily removed with a single screw...and with some light filing, cured.

There could be a burr anywhere along the cartridges path of travel...the loading gate though is the easiest to examine first.

Good luck

[deerwhacker444]

I have a Remington 760 in 300 Savage that did that. It belonged to my Great Grandfather. Somewhere along the line, somebody stuck a cleaning rod into the chaber and created a burr of pushed up metal. The burr wouldn't scratch a case until it was fired. Then the case would fire-form around the bur and leave a nasty looking spot on the brass.

I fixed it with a flexible shaft dremel tool and a polishing bonnet. I put polishing compound on the bonnet and the grit quickly wore the burr down until it was flush with the rest of the chamber. I had to really clean the rifle good to get the polishing compound out of the action, but it doesn't ruin my brass any longer.

[Leverdude]

Probably from shovint them thru the gate. The inner edge of the loading port is usually pretty sharp.