Author Topic: How do I convert a Marlin 336 lever gun to .307? (Read 789 times)

Smokey · « **on:** August 30, 2003, 08:36:54 AM »

Is the best caliber to start with the tried and true .30-30 or is there something better?

What work needs to be performed for this conversion, on the barrel and on the action?

Thanks, in advance, for your advice.

gunnut69 · « **Reply #1 on:** August 30, 2003, 11:13:39 AM »

The easiest way may be to see if a barrel is available from Marlin or perhaps GunPartsCorp. I've not done this modification but would quess the 30-30 would be the place to start. both rounds are 30 caliber and rimmed. The prime differences being the case capacities and lengths involved. Good luck from the gunnut69

Chuck from arkansaw · « **Reply #2 on:** December 11, 2003, 11:54:14 AM »

Ream the chamber with a .308 yes I said .308 as in .308 winchester to the correct headspace, and shoot it. Everything else should work if you start with a .30-30.

Prince of Wales · « **Reply #3 on:** December 16, 2003, 10:42:30 AM »

Chuck this gets me to thinking. What about beginning with a 7/30 Waters and reaming the chamber for 7mm/08 then necking 307 brass to 7mm. Would the benefits outweigh the effort? Seems as if it would produce a sort of 7/30 Imp. Best of luck. POW

445supermag · « **Reply #4 on:** December 16, 2003, 10:08:49 PM »

First see if you can put a 308 through the loading gate of a 30/30 336! I am sure you will find a problem and it doesn,t have a rim. If you get all that working and the mag tube is large enouch and the carige is long enough and the barrel shank is large enough and the extractor is modified enough for the way bigger rim will the 336 action hold the working pressure of the 307 of 50,ooo psi. I think not. The win 94 big boar is not the same action as94.

gunnut69 · « **Reply #5 on:** December 17, 2003, 05:54:49 AM »

The 307 is a rimmed version of the 308. It was chambered in the 336 along with the 444 and 45-70. Even with the much larger case head to push against the 45-70 in the marlin is rated as strong or stronger than an 86 winchester although not as strong as the ruger No.1 and Browning's Highwall. I don't know about the loading gate but strongly suspect since the case heads are very nearly the same, that the loading gates will work just fine. Also I don't know the working pressure of the 307 but since it IS a cartridge the rifle was chambered in it should work OK..

John A · « **Reply #6 on:** December 19, 2003, 05:27:04 AM »

Quote from: gunnut69

The 307 is a rimmed version of the 308. It was chambered in the 336 along with the 444 and 45-70. Even with the much larger case head to push against the 45-70 in the marlin is rated as strong or stronger than an 86 winchester although not as strong as the ruger No.1 and Browning's Highwall. I don't know about the loading gate but strongly suspect since the case heads are very nearly the same, that the loading gates will work just fine. Also I don't know the working pressure of the 307 but since it IS a cartridge the rifle was chambered in it should work OK..

I don't want to ruffel any feathers here but the 336 was never chambered in 307 only the 356. There has been a bit of talk about this modification over at the Marlin web site and it has been noted that some folks that have rechambered there 336 rifles in 30-30 to 307 have experienced sticky extraction when using factory 307 ammo. Was this the reason Marlin never chose to chamber any of there 336 ER's in 307, possibly the 307 ammo is running at abit higher pressure then the 356 factory ammo!

Chuck from arkansaw · « **Reply #7 on:** December 29, 2003, 05:17:04 PM »

The 7-08 conversion would be a good one, but is it possible to get a 7X30 Waters barrel for the 336? As far as brass, it is a dirty little secret that .308 brass will feed fire and extract in a .307, should work with 7-08 brass too. The main thing is to reload to pressure levels that will function in the 336.