To float or not to float... that is the question..

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Jason
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To float or not to float... that is the question..

Post by Jason » Sun Apr 08, 2018 5:32 pm

Short version: For the forend on my Marlin 336A, should I completely float the wood, bed about an inch near the receiver and float the rest, or bed the full length of it with high temp RTV?

Long version:
I had a well-worn mid-70s Marlin 336RC that shot well off the bench, but it had a short light barrel that was too light and had too short a sight radius to really compete with seriously. I shot a couple master scores with it, but it felt like a Red Ryder BB gun and waved in the wind with the slightest breeze so I decided to sell it and get a real CLA rifle. I ended up with a Marlin 336A from 1948 (the first year) that I was initially quite excited to get. I had heard about how much better rifles had been made then, with hours and hours of hand crafting goodness in every one with laser accuracy quite common. The outside hadn't been taken care of as well I would have liked (which lowered the price a bit) but the inside and the bore were pristine. Let me just say that I'm sure this rifle had never been shot much, because it was rough cycling with no visible wear anywhere. Even after a very thorough clean and lube, it was still very rough. I could tell from me cycling a few hundred times trying to figure out where the roughness was coming from that there were a few machine marks scattered throughout it that were now getting a bit of wear showing on them.I did my due diligence and polished and cycled until most of the roughness was gone. I tweaked and tuned until the two-piece firing pin travel was smooth and perfect. I worked on the trigger until it was a consistent two pounds (which would have been easier if any of the modern replacement triggers would have fit it). I even had it smooth and consistent enough that I could use the forward notch that gave more hammer spring pressure, taking the lever action lock time (compared to a Rem 700 clone) from about a week to only a couple days. It was ready.

I mounted a scope (including drilling/tapping, see "non-collector's item" comment above) and tried lots of different loads through the relatively tight chamber, and some shot OK but none were awesome. Even the "tried and true" loads posted here and other places didn't shoot great. I tried neck sizing only, then full length sizing so that I only bumped the shoulder back 0.002" (which incidentally required me to bottom the FL sizer on the shellplate because of the tight chamber). I tried those and other loading tricks that have resulted in accuracy improvements across very many bolt or auto-loading rifles. I got some small, incremental gains but nothing substantial. That lead me to start researching how to make a lever action rifle more accurate. The chamber, bore and crown all look fine, better than I've seen in some bolt action rifles that I've made shoot very well. That made me think that the issue was something unique to a lever action rifle, namely the wooden pieces.

The feedback on improving the buttstock is effectively unanimous, with pillar bedding being the best at making the connection solid and reliable. Since my rifle was no collector's item due to the external condition anyway, I didn't really about all the cautions against defiling such a classic I've now done that, and I do think it's a lot more solid. My intuition leads me to believe that the wood touching the barrel is a more likely place to interfere with accuracy, though, especially as the barrel heats up through a couple banks of animals. The feedback on what to do about the forend started out unanimous regarding relieving the pressure that the wood puts on the barrel, but the next step is where opinions diverge significantly with three major schools of thought.
  1. Float the barrel away from the wood completely and epoxy bed the ends of it on the receiver and the forend cap (or barrel band, which this rifle doesn't have). This would result in the barrel only being touched by the forend cap (or barrel band) and the magazine tube attachment point. There is very little at the receiver other than the barrel or magazine tube to brace the forend against, though.There was a fair amount of caution regarding the wood only touching the receiver and the cap (or barrel band), as it would shoot loose over time, damaging the wood and touching the barrel.When inspecting my rifle, this seemed like a reasonable caution.
  2. Remove enough wood to completely float the barrel, but epoxy bed the forend on the forend cap at the front as above but bed the rear of the forend on the receiver and an inch or so of the barrel at the receiver. This seemed more reasonable, as I have bedded some other rifles, especially those with single action screws like a CZ 452 Varmint or 10/22, through the action and the first inch of the barrel to provide support for the barrel.
  3. Float the barrel completely, epoxy bed the ends against the forend cap and receiver, and then bed the length of the barrel against the forend using high temp RTV gasket maker. Surprisingly, this was the most common feedback, with multiple reports of this improving accuracy of multiple models of lever action rifles.
I had never heard of using RTV to bed a barrel before this, and I still don't really understand it. After further investigation, all of the RTV bedding sentiments seems to find its roots in one single place. That place is a book called Accurizing the Factory Rifle by M.L. McPherson. There have even been a couple threads here on SteelChickens where this was mentioned, including this one.

Accurizing Marlin Lever Gun

That leads me to where I am today. I removed enough wood on the forend to completely float the barrel with the usual two business cards of space and relieved enough on the ends of it to epoxy bed the ends against the forend cap and the receiver. To have my bases covered for testing all three of the methods above, I also bedded the first inch of the barrel nearest the receiver. I have used the compressible rubber/neoprene washer when attaching the magazine tube and adjusted the tension on that screw so that it doesn't press up or down on the forend cap that closes tight on it when I tighten the screws on each side of the forend cap. That effectively completes method 2 above.

My intention is to shoot the rifle this way to test accuracy. If I can't get any of a few loads to shoot well, then I'll try one of the other methods. I'm likely not going to try method 1 extensively, as there is clearly very little to support the forend on the receiver end unless it's supported by the magazine tube or the barrel. I am likely going to go straight to method 3, so would be sanding away some of the epoxy bedding at the receiver and then bedding the length of the barrel under the forend with RTV gasket maker. I still don't understand why using a soft material as bedding material is a good idea. My understanding is that the idea of bedding actions, and even the first inch of a barrel or a pressure point on a stock, is to have a solid and consistent pressure as possible against metal. It's hard to argue with so many reports of positive results, though.

Can someone with more experience here help explain this? Has your experience made it clear that I'm wasting my time with method 2 so I should just jump straight to method 3 (RTV bedding) to save myself some time, components and barrel wear?

Thanks in advance for any guidance anyone might be able to provide.

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Jason
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Re: To float or not to float... that is the question..

Post by Jason » Mon Apr 09, 2018 8:24 am

Note that I also posted this in the lever action silhouette forum on the MarlinOwners site.

http://www.marlinowners.com/forum/nra-c ... stion.html

I got a couple good feedbacks, including one that helped clarify a few things.

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Re: To float or not to float... that is the question..

Post by Another Dang 9 » Mon Apr 09, 2018 8:33 am

Jason, I hope your efforts pan out but it may be much ado about nothing. Lever rifles are not known for their liking to custom work. To many factors hold it back. Barrel band, foregrip, ammo in the tube and more. My .357 Marlin would rattle the screws loose and accuracy went south till I blue loc-tited all of them. I would put more stock in a good rear sight over any other modifications. JMO.
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Re: To float or not to float... that is the question..

Post by Jason » Mon Apr 09, 2018 10:04 am

Thanks, but I already have the sight setup completed. I'm using my standard Lyman 17A front sight with a Lee Shaver insert and a Redfield 75 rear sight. Unfortunately, if the rifle doesn't shoot accurately enough it doesn't matter what sights are on it.

I've had some great improvements on accuracy with a few small tweaks with other lever action rifles, but this one has been more of a challenge. My previous centerfire lever action rifles have all eventually been able to consistently put five shots within 1.5 inches or less, center-to-center, at 100 meters after tuning and load development. I don't think that's a terribly tough bar to meet, but this one hasn't achieved that yet consistently even though it has done it occasionally. I try to control all of those variables that you mention and a few more. This rifle doesn't have a barrel band. It has a forend cap that I have now modified so that it doesn't touch the barrel or the magazine tube. I also don't shoot with any rounds in the magazine tube. I load each through the loading gate and then cycle it into the action for the shot. The only lever action rifle that I shoot silhouette targets with rounds in the magazine is my Marlin 39A. The 22LR rounds in the magazine made no difference in point of impact in my tests. Having multiple 30-30 rounds in the magazine in the 336 and 336A definitely did affect the point of impact, and even the 357 Magnum rounds in the magazine of my 1873 affected point of impact a bit.

Other than this last bit of tuning on the forend and possibly a re-crown (despite the crown currently looking fine), I think I've likely done all that can be done for this rifle. :lol:

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Re: To float or not to float... that is the question..

Post by frankmako » Mon Apr 09, 2018 6:32 pm

did you clean the barrel with jb bore cleaner. jb bore cleaner will get out a lot of junk even when you think the bore is clean. maybe the rifle does not like your current load. re work your loads to see what the rifle likes. i am all in for single load through the loading gate. i don't know if floating the barrel will do anything. bolt action rifle yes it does but a lever rifle i just don't know.

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Re: To float or not to float... that is the question..

Post by edgehit » Mon Apr 09, 2018 8:12 pm

Buy another rifle. Some of them just don’t shoot. When I started this game 10 years ago a wise person answered my question “how do you get a levergun to shoot?” Answer - buy 10 and keep the best one.

Other than that, try option 3.
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Re: To float or not to float... that is the question..

Post by Jason » Mon Apr 09, 2018 10:08 pm

frankmako wrote:
Mon Apr 09, 2018 6:32 pm
did you clean the barrel with jb bore cleaner. jb bore cleaner will get out a lot of junk even when you think the bore is clean. maybe the rifle does not like your current load. re work your loads to see what the rifle likes. i am all in for single load through the loading gate. i don't know if floating the barrel will do anything. bolt action rifle yes it does but a lever rifle i just don't know.
Yes, I cleaned the barrel with JB bore cleaner. It didn't make much of a difference. I have tried at least six different bullets and at least that many powders. I've talked to a few others and read about lots more that improved accuracy through the same methods that I'm trying now. I should know on Saturday whether it's better after the bedding/floating.

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Re: To float or not to float... that is the question..

Post by Jason » Mon Apr 09, 2018 10:10 pm

edgehit wrote:
Mon Apr 09, 2018 8:12 pm
Buy another rifle. Some of them just don’t shoot. When I started this game 10 years ago a wise person answered my question “how do you get a levergun to shoot?” Answer - buy 10 and keep the best one.

Other than that, try option 3.
I don't shoot that match enough to make it worth buying a bunch of rifles trying to get one to shoot. I also usually just make the rifle that I have shoot better. Most of the issues are reasonably easy to figure out once you've worked on a few of them. If I just can't make it shoot better, I've already got my eye on a Teddy Roosevelt edition of the 1894. We'll see, though. I haven't been beaten by a centerfire rifle yet, so I'm stubbornly going to try a couple more things with this one. I could probably get reasonably high scores with this rifle the way it was before since our lever action targets are so big, but I just don't have confidence if I know the rifle isn't as accurate as I want it to be. I also only need CLA turkeys to finish that grand slam to go with the other four grand slams. I've won matches with the rifle, but I want all the turkeys to fall. :D
Last edited by Jason on Mon Apr 09, 2018 10:14 pm, edited 1 time in total.

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Re: To float or not to float... that is the question..

Post by cslcAl » Tue Apr 10, 2018 11:36 am

Jason, I had owned 3 different 336A Marlins in the last 15 years. A 1948, 1951, and a 1949. I was not happy with any of them. What I found out was as the barrel gets hot impact shifts. One little trick you can try is to loosen the screw at the muzzle end of the magazine, so the magazine will float up and down instead of being tight against the barrel. I put a piece or tape over the screw head so it wouldn’t fall out if it backed out further.
I don’t want to offend any Marlin lovers, but I got rid of all the ones I had. I’ll stick to Winchester’s.

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Re: To float or not to float... that is the question..

Post by cedestech » Tue Apr 10, 2018 11:47 am

cslcAl wrote:
Tue Apr 10, 2018 11:36 am
I’ll stick to Winchester’s.
I've had 4 - '94s so far... all 26 octogon barreled and every one of them shoot very well. They have their own ism's but when you break the sear and light the fire that round lands way close enough to where you have it aimed for this game... Hot or cold... :)

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Re: To float or not to float... that is the question..

Post by SqHunter » Tue Apr 10, 2018 5:33 pm

Our two Marlins are all touchy about how the forearm is held when shooting, either from the bench or offhand. I am not sure why the .44 acts the way it does, but the forearm on our 39a was terribly loose and ill fitted. I have now glass bedded the forearm, but I also later found interfernce with the forend cap. This might have been the problem all along as it hit the barrel on one side pretty hard and made the forearm hang improperly, but naturally I did not find the issue till after the glass had hardened :shock:

Anyway, I am not sure if it was the glass that fixed our rifle or free floating the forend cap, but it is much more stable and less finicky now.

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