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Discussion Starter #1 (Edited)
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.
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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I use RTV bedding on the fore ends along the barrel. Where the fore end meets the receiver and the end caps I used an epoxy i and noticed a small improvement in accuracy.
I got the biggest improvement by relieving the fore end tension against the pinion that the end cap attaches to.
 

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Discussion Starter #4
I use RTV bedding on the entire fore ends of my 336A and my 30AS and noticed a small improvement in accuracy.
I got the biggest improvement by relieving the fore end tension against the pinion that the end cap attaches to.
Steven,

Can you give me a bit more information about relieving the tension against the tenon? Do you mean that the forend wood was too long for the space between the receiver and the tenon that the end cap attaches to or something else? I had to file a bit of wood on each end to relieve tension and make space before I glass bedded the ends into the forend cap and receiver. I did notice that when I screwed in the forend cap screws that the forend cap tightened down on the magazine tube. If I then screwed in the screw in the end of the magazine tube all the way in, it pulled the magazine tube much closer to the barrel than the forend cap was allowing it to go to the point that it was noticeably bending the tube from the pressure. That lead me to more research and I eventually found that was common for models with forend caps instead of barrel bands, and the usual fix was to use some sort of spacer like a rubber or neoprene washer over the magazine tube stud in the barrel and blue loctite on the screw. That would securely attach the magazine tube without putting pressure on the barrel at the magazine tube stud and the forend cap tenon.
 

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Steven,

Can you give me a bit more information about relieving the tension against the tenon? Do you mean that the forend wood was too long for the space between the receiver and the tenon that the end cap attaches to or something else? I had to file a bit of wood on each end to relieve tension and make space before I glass bedded the ends into the forend cap and receiver. I did notice that when I screwed in the forend cap screws that the forend cap tightened down on the magazine tube. If I then screwed in the screw in the end of the magazine tube all the way in, it pulled the magazine tube much closer to the barrel than the forend cap was allowing it to go to the point that it was noticeably bending the tube from the pressure. That lead me to more research and I eventually found that was common for models with forend caps instead of barrel bands, and the usual fix was to use some sort of spacer like a rubber or neoprene washer over the magazine tube stud in the barrel and blue loctite on the screw. That would securely attach the magazine tube without putting pressure on the barrel at the magazine tube stud and the forend cap tenon.
Yes. Before I did that the fore end was a bit too long and was wedged between the receiver and the end cap tenon. A sanded just enough off the length of the fore end so it wouldn't put tension against the tenon (taking it off the end with the end cap).
As for the end cap pulling on the mag. tube I opened up the hole that the mag. tube passes through with a fine rat tailed file.
 

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Discussion Starter #6
As for the end cap pulling on the mag. tube I opened up the hole that the mag. tube passes through with a fine rat tailed file.
I didn't think of that. I think I'll go check to see if the magazine tube in mine will clear the wood and the forend cap tenon tightened all the way down without the washer on the stud. If so, it will only take a few minutes with a file on the forend cap and some cold blue to make that no longer an issue. Thanks!
 

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Discussion Starter #7 (Edited)
Well it took more than a few minutes and I had to remove just a bit of wood along the magazine tube channel along with the metal of the forend cap. It's done now, though. The magazine tube is screwed all the way down against the stud with no spacer, and there's nothing touching the magazine tube between the receiver and the magazine tube stud on the barrel. I even spent the time to polish and oxpho blue the forend cap so it looks decent. The barrel is as free of pressure as it can get with stuff hanging off of it. I should have time one night this week to load a few test loads and get to do some testing Saturday afternoon after our smallbore and pistol cartridge lever action silhouette matches. Hopefully all will be well and I'll be able to find a couple good loads for the centerfire silhouette matches. Then I can yank this ugly scope off my lever gun and put on a proper rear sight. :biggrin:

Thanks again for the help! :top::adore:
 

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Here is a couple of 5 shot groups at 100 yards. It was a Cowboy but the other Marlins respond just as well.



Yes, the lever gun can be made to shoot. No one believes how I do it so I don't post such things on open forum. If you are really interested just PM me with your phone number and best times to call, I'll call you.

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Jason,

I think that you are almost there. I have found the following to give me the most consistency/accuracy (for paper-punching):

1. Bed butt-stock to rear of receiver (and if necessary bed screw holes to ensure no-wiggle under recoil).

2. Very slightly shorten fore-end wood between front of receiver and end-cap to ensure a no pressure fit (may need to bed fore-stock to receiver contact-area and fore-stock to end-cap contact-area to stop wiggle and ensure consistent alignment) {you need to "free-float barrel first to get this right}

3. Make mag tube "rattley" by relieving any contact areas between mag tube and fore-stock and mag-tube and end-cap, and by ensuring magazine end cap stud is finger-pressure loose from side-to-side in barrel dovetail. Use a dot of adhesive Velcro (fluffy side) on each side of the wood in the fore-end near the end-cap to stop magazine rattle from being annoying while carrying/shooting.

4. RTV bed the barrel to wood contact along the fore-end channel. This is to mostly stop the wood from "shooting-loose" with the tiny bedding contact areas at front of receiver and end-cap, it needs to be resilient/springy as you're not trying to put any pressure between fore-end and barrel or trying to hard-bed as you would a one piece stock.

5. Modify your bag/shooting-rest technique and expectations from that used with one piece stocks when accuracy testing. - Use very soft bags, or prone-supported-position when testing loads. Alternatively play around with a known accurate low-velocity plinking load on your bags/rest until you find the sweet spot for consistency before checking your target loads. For testing CLAS loads I suggest shooting multiple 10 shot groups rather than 5 shot groups when accuracy testing, as the 2 piece stock and working the lever will always create a few "looser" shots. I've attached a photo to show how a 10 shot group can give a bit more information/confidence in your lever action target loads than 2* 5 shot groups.

10 shot.jpg
 
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