Marlin Accuracy Problem. What to do?

[fnbrowning]

I bought my Marlin 336 in .30-30 used about 11/2 years ago. It was manufactured in 1976.  I have never been happy with itÂ’s accuracy. Now IÂ’ll state right off that I realize this type of rifle, a carbine with a light weight barrel, is not a tack driver. I was quite aware that as the barrel heated up, I could expect the group size to increase.

But in forums like this, I often read reports of fine shooting with the Marlin rifles. Some time back on the old Marlin forum, they had a shooting contest where the contestants mailed in postcards of their groups.
I was amazed and perplexed. Some of those guys were getting almost MOA, and I could not equal even the weakest examples.

I tried deep cleaning a polishing the barrel with JB bore paste, different loads, no avail. The best I seemed able to do was a group in about oh, 25 sq inches. So when my friend and I sent other rifles out for a cryo-treat, this Marlin went also.

The groups did improve. I can now hit the 10 ring at 100yards several times in a string. Problem solved, right? Not quite. Now the Marlin shoots 3 -4 inches high on the first round, and then drops down and groups on subsequent shots.

IÂ’ve tried electronic cleaning of the bore. The front band was pulling the magazine tube toward the barrel, so IÂ’ve machined the front band to relieve about 70% of the stress there. Below is an example of the group with factory ammunition.



As you can see, the first shot is quite high. The picture shows Remington 150gr Core-Lokt. Winchester 150gr Power-Point doesnÂ’t jump quite as high, but the effect is the same. My reloads with 130gr Speer jump higher.
After the 1st shot, loads groups reasonably well whether it is 2, 4, or 6 more rounds.

As you can see in the photo below, the bore copper fouls quite extensively.

Those are actually the groves, not the lands. In bright light, there are as bright as a penny. And thatÂ’s after a half dozen patches with a name-brand copper remover!
The marred portion of the barrel near 12:00 was there when I bought the rifle. DonÂ’t know if the previous owner dropped the gun, or bumped a brick wall or what.



I donÂ’t think a 3 - 4 inch jump is acceptable, even for a 20" barrel.
The only thing that I can think of at this point is a rebarrel. At this point, IÂ’m open to suggestions.

[VTDW]

I had the same problem with my 336W. 8 inch groups at 100 yd. After shooting 7 different brands of ammo I chose the Hornady 170 gr. factory stuff. That helped quite a bit but ended up shooting 3-4 inch groups on a good day at 100 yd. I finally decided to take off the forend and relieve the wood in the channel where the barrel rests. Talk about making a huge difference. I am down to 2 inch groups and am going to take the forend off again to see if the thing needs any more relieving. I am fairly happy with the 2 inch groups for hunting. Also, just make sure the barrel bands are just snug and not tight. That can make a big difference also.

Dave

Get a can of WipOut and your copper troubles will go away.

[Mikey]

fnbrowning:  I can see two problems when looking at the picture of the end of your barrel.  Yes, you show serious copper fouling but I also see a noticeable ding at the crown.

I would suggest two efforts:  One, get that ding removed - usually a gunsmith can recrown the barrel without too much of a problem.  That should help.  Also, go to the Beartooth Bullet web site or to Veral Smith's forum down the line here at Graybeards, and get a bore lapping kit.  Yes, you can polish your bore with JB paste, but that does not have the same beneficial effect as fire-lapping.  Firelapping will eliminate your copper fouling problems and your rifle should shoot more consistently and accurately.

HTH.  Mikey.

[fnbrowning]

Someone else wrote:

I think what was suggested is that you remove EVERYTHING forward of the receiver except the barrel and front sight. Rest the action on the bag and shoot a group(s). It won't be at all difficult to control a .30-30 resting on the bags. Don't rest the barrel on the bag. Perhaps that will give you some idea of the problem.

I will do this. The more I thought about it, the better the idea seems. I will try to do the test this weekend. Will post results.

I would suggest two efforts:  One, get that ding removed - usually a gunsmith can recrown the barrel without too much of a problem.  That should help.  Also, go to the Beartooth Bullet web site or to Veral Smith's forum down the line here at Graybeards, and get a bore lapping kit.  Firelapping will eliminate your copper fouling problems and your rifle should shoot more consistently and accurately.
HTH.  Mikey.

Yes the suggestion helps. However, I will wait on this to see if the rifle improves from relieving stress points.
If the barrel keeps jumping from cold 1st round with no magazine tube or forearm, then I'll just replace it.

[big medicine]

Is the first shout of a clean barrel?

I found that my 336 30-30 carbine doesnt shot the 150 gr bullets very well. I'm working up loads for the 170 gr and it is looking much better.

[fnbrowning]

Is the first shout of a clean barrel?

I found that my 336 30-30 carbine doesnt shot the 150 gr bullets very well. I'm working up loads for the 170 gr and it is looking much better.

First round jump comes from a "cold/cool" barrel. I tested for a couple of hours to let the barrel cool between strings.
Clean or "dirty", the 2nd to 3rd {or 6th} shots group with fine accuracy for a lever action carbine.

[fnbrowning]

Well, I removed EVERYTHING forward of the receiver except the barrel and front sight. Rested the action on the bag and shoot a group(s).

Tests were done with Federal American Eagle 150gr, Remington 150gr, Winchester 150gr. And my 130gr Speer reloads in that order. The barrel was clean, but not completely de-fouled. It takes a lot of work to completely de-copper the barrel. .  I tested for a couple of hours to let the barrel cool between strings.

The first round from the Federal ammo jumped from a "cold/clean" barrel, right off the paper!
As the test wore on, the jumping became less pronounced, but the groups opened up.

Seems the copper fouling has a direct impact on the group size


That having been said, the barrel does need a lapping and a recrown, with no guarantees that it will solve all the problems. IÂ’ve never been happy with the accuracy as IÂ’m unable to duplicate the modest groups so often reported here and at other forums.

Therefore, I will begin looking for a really nice replacement barrel from a reputable manufacturer.

[jvs]

Your problem may be from the barrel being shot out.  Since you bought this thing used, the old owner may have well over 500 shots through this barrel.  Micro-groove rifling is not made for infinity, somewhere around 500 to 600 shots these barrrels show alot of wear and begin to open up at the range.  Since you have visible copper fouling I would think that your bullet is flopping its way down a shot out barrel.  Used cowboy guns take a beating during competitions and then are sold to unsuspecting buyers by what I believe are disreputable dealers.

Taking care of the crown is not one of the things that should wait, it is one of the first things to check on any rifle, including a Marlin.  It doesnt take much of a ding in the crown around the bore to make a bullet go wild.  Then again, if you replace the barrel, the crown will also be taken care of.

[fffffg]

..  ive done the  improve the gun thing for years, and it does very little to improve groups..  your second and third shot shows that the crown is ok as they are in the same moa that is accepable??..   what i see is a loading problem..  your first shot has a higher velocity as there is no fouling in the barrel and pressures are lower letting the bullet move faster.. the second rounds are under more pressure..   so to get good groups with this kind of gun they are designed for a healthy crimp.. this will give better burning and less fouling makeing the velocity variation less..  more powder will also help but stay in the guidlines and start at the minumum load...  ive talked to some darn good shots and they have said powder is the most siginificant /important in getting good groups..  you have a short barrel and this again points to a crimp problem..   set the crimp tight and  trim cases ON EACH LOADING. this is important for good groups..  then with each loading shoot one group with   no washer under the seating die.. .. then cut two or three washers out of a manila file folder.. then use one for the next grouop , then two washers from the folder to lighten the crimp.. the correct crimp will become apparent.. try five different powders at minimum load and work up to max, watching signs of  high pressure.. this gun will shoot with the better marlins seeing your group..  itis perfectly in line left and right, this means the barrel and most accuracy problems are fine..  the  bullet is grouping well afte fired so it shows the gun is set up right..  wehn i go to the range i usually try three shot groups with three differnt bullets, three diffeernt criimps on each, and ultimatly try 5 powders..you can find the best bullet of the tree and stick wit that.. make sure they are not all the same weight/lenth.   youll get it and my guess itwill shoot fine if you havent done too much accurizing..  . 3031 will shoot clean if its pressue is right, as an example, then iv had it smoke like black powder when its not under the right pressures..   you didn give me enijgh targets to totaly evaluate this  , becouse you should have used 5 shot groups, showing the sequence with clean bore., then let the gun cool with dirty barrel an do it again ,, this would tell a lot more..  if it still drops with a  dirtyh barrel after first shot  i would have to think about this, but could still be fouling as it could shoot higher with less pressure.. it depends on your body postion on the gun, how tight you hold it    etc..  the groups oopening up after shooting for awhile happens to me regularly because i loose consentration..   the key is to move slow change one thing at a time.. it seems your moving mountians when you should be using teaspoons and analizeing the data as you change the teasoon.  i finnaly got a drilling to shoot a very fine group at 30 yards (bad eyes) a little while back after three months of working loads,, turned out the bullet had to be moved out to within 1/4 inch of the bullet   holding in the case...  darn europeans..  the lead bullet was strippping with heavy loads and the long jump.... jacteted bullets are not availble in this strange caliber.. these lever  guns seem to shoot well with heavy crimp to stop the bullet from seating deeper in the tube, and with reasonbly hot load, but let the gun tell you what is going on, not you tell the gun what it is to do.. good luck dave...

[oso45-70]

fffffg,
Dave you have hit the nail on the head. I have found that if i'm trying for groups i will shoot one off to the side and the start my groups. When i was guiding hunters i would have them shoot a couple rounds for foul out and then have them shoot three for group and not let them clean the barrel.
On long range shots i've seen hunters over shoot and i know some of it was that first shot going high. Have a good one.........Joe..........

[fffffg]

thanks..  i also remembered last knight..  crimp in the canalure becouse it is the only place youll probably get the bullet to stay in position when going thru the tube on a lever..  get a calipers, inertia bullet puller and flat nose bullets..  load three rounds without powder and fired primer and run the bullets thrue the tube and chamber three times and measure the overall lenght to see if it is colapsing..  the rifling can touch the bullet one one side or scratch one side of the bullet lithtly but it should not be tigght in the chamber.. normally 1/16 inch short of the rifling..   the two rounds so close totgher in the second and thired shot show you have a fine shooting rifle. you need to find the correct bullet length, powder charge, crimp  and bullet to do the job..  i enjoy this part. when i get a gun shooting well there  doesnt seem to be any reason to shoot it any more.. but when its acting up its me and that gun and reoladeing press for useually days , or weeks, and as i stated that darn drilling i shot three shot groups most mornings for several months..  but when your an old man what else is there to do?..  good luck dave..

[Garthag]

Half-inch-group,
  Just got a M1895 Cowboy, only my second lever gun and first big bore.  Is a 600-shot barrel life what I should expect out of it?  I understand that there are some bullets out there that are pretty hard, but I have shot thousands of surplus rounds through my other rifles and haven't noticed a difference.  Many of those rifles have chrome lined barrels, but Yugo SKS's do not and I'm sure they have a service life much greater than 600 shots.  I don't imagine a FMJ bullet going down the barrel of a SKS would wear less than a similar bullet in the Marlin.
  Either way, I probably will never find a case of .45-70 for a price that I can afford without selling a kidney, so it will probably take me years to reach 600...

[Greybeard]

NO. There is no reason a Marlin Micro Groove barrel will not last your life time and that of your children also. Stories of such short barrel life have no basis in fact. Ignore them and enjoy your rifle.

[Leverdude]

NO. There is no reason a Marlin Micro Groove barrel will not last your life time and that of your children also. Stories of such short barrel life have no basis in fact. Ignore them and enjoy your rifle.

I'll second that, Never heard something so rediculous in my life, well, maybe some things.     Seriously tho a Microgroove barrel will last just as long as any other. Why would anyone buy a gun wth a 500 round life expectancy? I'v shot more bullets than that from my 336 in a weekend.
That said I do have one that was shot out but it is 50 years old & the chamber was shot, the rifling was fine it was just real hard to extract & the fired cases were balooned out. That barrel was pre Microgroove.

Cant say what your guns issue is but you'v got some good advice above.
My first thought was the first shot was coming from a clean barrel but since thats not the case I would start with stress ponts myself.

[guntech59]

Glad to hear that!!  I just bought a new Marlin 336cs in .35 Rem.  (Well, used but less than a box of ammo through it.)  That post had me worried for a minute.

Phil

NO. There is no reason a Marlin Micro Groove barrel will not last your life time and that of your children also. Stories of such short barrel life have no basis in fact. Ignore them and enjoy your rifle.

I'll second that, Never heard something so rediculous in my life, well, maybe some things.     Seriously tho a Microgroove barrel will last just as long as any other. Why would anyone buy a gun wth a 500 round life expectancy? I'v shot more bullets than that from my 336 in a weekend.
That said I do have one that was shot out but it is 50 years old & the chamber was shot, the rifling was fine it was just real hard to extract & the fired cases were balooned out. That barrel was pre Microgroove.

Cant say what your guns issue is but you'v got some good advice above.
My first thought was the first shot was coming from a clean barrel but since thats not the case I would start with stress ponts myself.

[CJ]

I'll THIRD it. My .35 has well over 1200 rds through it and still shoots tight groups. Ive had it for years and bought it used.

[Garthag]

Thanks for the replies and the peace of mind!

[palgeno]

Yeah, me too----I was worried that 336 in .35 rem that I bought in 1965 was  no good anymore ---the last couple thousand rounds after the first 500 were just faking me out when they hit that target center or killed those deer!! (Actually I killed a lot of  raccoons with and very few deer it in those early hunting years.) pg

[papajohn428]

I'd be willing to bet if you shot nothing but cast bullets thru your Marlin, and didn't clean it to death, you could get 50,000 rounds out of it before the accuracy dropped off.  Now if you rechambered it to the 17/50BMG Eargesplitten Loudenboomer Magnum, you might have some issues to deal with!  Shoot those Marlins, they like it.    500 rounds, yeesh, how do these things get started?

PJ

[rickt300]

I'd say get rid of that barrel and start over. I have never seen a Marlin that fouled up. The cheap way would be to go 30-30 but 25-35 Tomcat is where it's at!

[TennesseeNuc]

fn,
I'd vote for a new barrel from Marlin.  They do good work at reasonable prices.  It would be woth it to get rid of the stress that the thing is causing.
Best,
TnNuc

[Pat Marlin]

No... that's right!  Micro Groove Marlin rifles wash out at 600 rounds.

That being said, they're worth about $50.  I'll buy yours so you can get a new one..    :-D