Old Marlin 336 keyholing.

R

Rock Knocker

Active member
Sighted in a few rifles today getting ready for WS rifle season and my buddy's grandfather's old Marlin 336 was keyholing with Leverlution 160gr ammo, keyholing groups just as tight as my Winchester factory ammo flying straight but that's a different story.

I didnt see the twist rate and he said it's unlikely to have been cleaned this decade...

160grs a bit too heavy?
 
The .30-30 traditional loadings are 150 and 170 grain bullet weights. The 160 gr. is not overly heavy. I would try some plain old 150 and 170 gr. cup & core Remington, Federal and Winchester ammo. The .30-30 doesn't need fancy bullets to perform well.
 
I will let him know, there was a spare 30-30 around that shot the same ammo subMOA so he is going use that one hunting but I saw an old box of 170gr in the safe, I will tell him to try those. I figured going up in weight wouldnt help much with stabilization but I've fired maybe four shots through a 30-30, figured they had that round ironed out by now.
 
Round nose bullets will stabilize with a slower twist than a spitzer of the same weight. I don't know what twist Marlins have had through history, but I have one from the 70's I think that will put the 160 ftx into unbelievable groups.
 
Round nose vs. spitzer, I forgot about that, I suppose most 30-30 bullets are traditionally pretty rounded and the new Leverlution was a spitzer with a bouncy rubber tip on it.

I checked down the bore and around the crown, at first looking around the crown I thought the bore was worn smooth, oh boy I thought "how the [beeep] could that happen to a 30-30" but after shining a light into the action and looking down the barrel I saw rifling I hadn't seen before. After looking it up I believe it was their 1-10 twist 12 land and grooves.
 
That 160 gr bullet is longer than the flat and round-nosed versions - twist MAY be an issue, but of what I've seen, most people in most 30-30's were getting very acceptable accuracy with them. Also, a good cleaning MAY just straighten things out for you.....esp if you're having trouble seeing the lands.
 
Originally Posted By: Mike BThat 160 gr bullet is longer than the flat and round-nosed versions - twist MAY be an issue, but of what I've seen, most people in most 30-30's were getting very acceptable accuracy with them. Also, a good cleaning MAY just straighten things out for you.....esp if you're having trouble seeing the lands.
+1
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Marlin used "micro grove rifling" in some of there rifles so as you do not see bold rifling it just may be micro rifling. Their theory was micro rifling didn't foul as bad.
 
Leverevolution adverstises higher velocities. Hornady's theory that faster is better may not be true for every caliber/platform. I tried it out of my 336 and wasn't impressed. I had the best results with 170 sp's in my rifle. I would see if you have keyholing issues with other loads. If not...then Leverevolution is the issue and you should stick to what works.
 

Older rifles sometimes have oversize bore.
I have a Winchester 94 that did not like store-bought ammo.
I slug the bore and found out it was oversized.
I had to buy .381 bullets for it, 38-55.
Then, I had to buy brass that had thinner wall.
So it would chamber the round. It shoots great now.
Shot a nice buck last year with it.
These older rifles are just great to hunt with.
RCBS sent me an oversized mandrel for free and I use a Lee collet crimping tool.
 
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