To float or not to float... that is the question..
Posted: 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.
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.
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.
- 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.
- 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.
- 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.
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.