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Discussion Starter · #1 ·
I started building my own 307 out of an '82 336 30-30 just to see if I could do it. So far I have reamed the chamber to where the lever clicks closed just right on the go gauge. It stops about an eighth of an inch from closed with the no-go gauge in it. There is only a 4 thousandth difference between to two. I made up a dummy round with a Speer 170gr. and new 307 brass. It feeds from the tube fine but kind of cross binds trying to go into the chamber. I spoke to Regan N. about it and he had a couple of suggestions. It could be shot now but, I think I'll wait until I get it to feed properly first. If anybody else is interested in this kind of conversion I'll post some more as it comes along. Rick
 

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When I do mine (which means I'll have to get ANOTHER Marliln as I'm not giving up the .30-30), Regan N. will be doing mine.

Keep us posted - I'm sure others besides myself are interested in how it goes. The .307 was what interested me in Marlins to begin with, couldn't find one and went with a .375 instead.
 

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You might have to tinker with the lifter. I'm just guessing but seeing as the 307's a fatter case a 30/30 lifter might raise it a bit too high to chamber nicely.
 

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lantrad said:
If anybody else is interested in this kind of conversion I'll post some more as it comes along. Rick
Please do keep us posted - with details.

Thanks :D :D
 

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If you have photos of your job, showing steps, or before and after on each modification made it would be a great resource to put in reference forum. :D :D :D
 

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Discussion Starter · #7 ·
Well, I know I said I'd wait until I got the feeding problem sorted out but, I loaded up some soft loads for it and took it to the range. No chrono just wanted to fire it to see if anything else might need some attention. I used Lee's second edition and Speer as references and decided on AA-2520 for the first powder to try. I used WLR primers and Speer 150gr FN bullets. It was 84 degrees today at the range. I've read of others with this conversion having trouble with anything over starting loads. Lee lists the AA-2520 starting load as 39.6gr. For this round I started at 38gr and reached 40gr in half grain increments. No sticking or anything else unusual showed up. The 38gr didn't even reseat the primer. Real pleasant to shoot. 40gr started to feel more like my 356ER. The next trip I'll try 40.5 to 42.5 in half grain increases. Lee lists a max load of 44gr at 45,500 cup for this combination. The chrono will tell the story. Still need the time to take it back apart and work on that loading issue. Sorry no pics. Tech notes? I'm just a tinkerer. I wanted to see if I could do this on my own after reading everything I could find for the last couple of years here and at Beartooth. I'll be glad to answer any questions if that would help. I've got a camera but haven't had time to learn to use it yet. One of my buddies is eyeballing this project to see how well it works. If I can reach good velocities with this, he wants one also. Maybe I'll figure out the camera by then. Later, Rick
 

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Hello Riflemen-Nice work lantrad. this conversion is ne that I have had my mind on for some time. That you are doing it and posting your research on this 307 has me looking for another Marlin for a project. Any information you can offer on this is most appreciated. The handloading data is very useful as well. thanks and Life is good, BestLever
 

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If we could get a 180 grain 30-cal bullet going about 2300-2400 fips safely from a converted Marlin, then I would get on the wagon too! That would satiate my lust for 30-40 balistics in a light handy scoped carbine. There's nothing in the lower 48 I wouldn't hunt with that out to 200 yards or so. For my money, a 336SC with that capability would be way sweeter than a Winchester 1895 chambered for the Krag round.
 

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Big Redhead said:
If we could get a 180 grain 30-cal bullet going about 2300-2400 fips safely from a converted Marlin, then I would get on the wagon too! .
In my .307 Winchester the 180 grain Hornady round nose will get 2479 fps from 40.0 grains of IMR 4895. I have limited experience with the .300 Savage but a 22" Savage 99 I played with came up up just under this velocity. A 22" .30-40 Krag will equal the 20".307 using published load data in the Krag cartridge.
There is a fly in the soup in that the Hornady bullet starts to taper at the cannalure and this leads to some crimping problems when you begin to lightly compress the powder charge.

Two loads I like better are the Speer 170 grain bullet with 43.0 grains of Alliant Reloder 15 for 2470 fps. This is one of those loads that reaches maximum pressure with some compression of the powder charge. Everything reaching a stop point together. I have shot this load a lot and at high temperatures - above 100 deg. without difficulty.

The 170 grain Speer or 170 grain Nosler Partition both do well with 43.0 grains of Hodgdon Varget for 2430 fps and perhaps just a little better accuracy than Reloder 15.

These loads are as hot as I want to go in my rifle but they are fine for both hot and cold weather. Loaded to a cOAL of 2.55" they all compress the powder charge.
 

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Hi Lantrad,

Is this a project an amateur like myself could do? What kind of special tools do you need? I've wanted to tackle something like this for a long time. I can take any gun apart and put it back together without having too many parts left over but I have never knocked the barrel out of a gun and put it back on. Marlin .30-30's are cheap in pawn shops in Texas.

Thanks,

Blowtorch
 

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Anyone done a 307 on a 24" barrel? I have an A that has been bubbafied. Wonderful shooter but no collectors value. Would 2600 with 170gr bullets be attainable with the longer barrel?
 

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Discussion Starter · #14 ·
Sorry I haven't posted but I'm in the process of doing a tear-off and re-roof on my mom's house. That and trying to keep 629 pieces of medical equiptment running 24-7. I haven't had time to go to the range or anything else yet. So far all I have used are hand tools. I want to see if it will handle the loads before going into too much detail. Not that there is much detail so far. :roll: If everthing works, William Iorg and I are going to run simultaneous brass expansion tests between his W94 and my Marlin 336. I haven't got a good caliper as yet. The next round of loads will bring it within 1.5 grains of max. If it handles that without any obvious pressure signs then I'll take it to max load. Later, Rick
 

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Discussion Starter · #16 ·
Well, as I only had to finish the ridge cap on my mom's roof this evening I called my buddy Miles and we went to the range. He wanted to shoot several loads through the chronograph and brought 3 guns. I only took the 307. I tested 4 rounds each of 40.5, 41, 41.5 42, and 42.5 grains of AA-2520 behind the 150 gr. Speer. All went well. 42 grains was interesting in that it posted 3 shots at 2569 and 1 at 2574. 42.5 was centered around 2600. I'll load the final rounds of 43, 43.5, and 44 grains soon. I don't know if the max load of 44 grains will reach 2700 or not. It'll be close I suspect. I'm going to try chamfering the barrel edge to help the loading problem. If that doesn't work as well as I want I have an idea to make something similar to the lifter on the 336-44's. That works great and makes for a straight line push into the chamber on my 44. I'll try the easy way first and see what happens. 2600 fps with a 150gr bullet ain't bad. The gun functions fine at this level. Anybody know what they get out of their 30-30 with this bullet? Thanks, Rick
 

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Discussion Starter · #17 ·
I got back to town as fast as I could this evening. Grabbed my gun and headed to the range. Got everything set up and the battery in the chrono was dead. :x Well, I went ahead and shot 2 rounds each of 43gr and 43.5gr of AA-2520 behind the speer 150. Then I shot 4 rounds of the listed max load of 44 grains. Everything seems fine. No sticking. primer flattening etc. It'll handle these loads with no problem it seems. Now I have to get back out to check the chrono data. I wondered about what another poster said about the loading problem being the reason Marlin didn't produce the 307. I tried a round in my 336ER to see if it would chamber properly. It hung just the same as in the converted one. Apparently the larger bullet helps line up the 356 as it is slick to chamber. Anybody got any favorite 307 loads to list to give me something to compare to? May get to the range tomorrow. Just went to Wally World and got batteries. What is everybody else getting out of their 307's? Thanks, Rick
 

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lantrad,

What kind of primers are you using with AA2520? I shot all my reloads before I got a chrony but checked factory loads and w/the 150gr bullets I avg. 2575fps from a Winchester. I just purchased Reloader 15 the other day and am waiting on dies to come in from Midway to start reloading again.

Here is a link that might help you compare you loads, or try new ones.

http://www.loadswap.com/display.php?action=view_weight&cartridge_id=60&table=Rifle_Data

I look forward to hearing your results.

John
 

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Discussion Starter · #19 ·
I didn't have any pages today so I went to the range. Shot up the rest of the reloads through the chrony. Just for reference here is the load.
MAX LOAD as listed in Modern Reloading, 2nd Edition, by Richard Lee
Brass----New Winchester 307
Bullet----Speer 150gr Hot Core bulk from Midway
Primer---WLR-Winchester Large Rifle
Powder---AA-2520 44 grains is listed as MAX LOAD
8 rounds fired through the chronograph listed in order.
2661-fps
2672
2682
2672
2661
2682
2661
2688
First time I've ever seen such a bunch of same numbers. Makes me kind of wonder about the chrono. :roll: Didn't make 2700fps but oh-well. I was at the gun shop afterwards and the gun smith who picks up work there showed up while I was still there. He looked over my work and the spent rounds and said it looked like a very good job. We talked about the loading issue some also. Him checking out my work gives me confidence that this can be done with only hand tools by most anyone who has a little ability and some patience so now I want to hear about some of you trying this also. I got lucky and was able to borrow the reamer and gauges. If you had to purchase them you might be money ahead to get a smith to do it for you. I wonder what it will take to make a 7-07 :twisted: Rick
 

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Discussion Starter · #20 ·
I was going back through the post to see if I'd answered all of the questions and realized I hadn't ever given a description of how I did it. :roll: All I did was use a vice, 3/8ths drive extension, 3/8ths drive torx[don't remember the size] and a 3/8th inch variable speed drill. I left the barrel on the receiver. One of my craftsman extensions is about the same size as the bolt so I used the bolt hole in the receiver as the guide. [LOTS of oil] I chucked the torx in the drill backwards and used it as a 3/8ths driver for the extension. I had intended to try and ream it by hand. That would have taken forever as the front shoulder of the 307 is larger than the rear of the 30-30. I started it by hand to get it centered at the rear. The pilot is not long enough at this point to align in the neck. It takes a little ways to engage the pilot. Then I had to learn by feel how fast to run the drill and how hard to push. It's firm but not hard. You want it to continually cut with light pressure. Faster cuts smoother but if you aren't pushing hard enough it can wobble outward. Too fast can gall things. Slower can be uneven and bumpy at the shoulder. Hand reaming can get real uneven. Like I said, it's a by feel thing. You have to learn how fast you are going to accumulate shavings and when to stop and clean. It's quicker than you think. If you think it might be time, stop and clean. I think I removed the reamer about 30 times or more. You don't want to have too many shavings and have them gall the throat. Get the reamer completely clean each time. I used a toothbrush to clean between the flutes. This all sounds worse than it is probably is. You need to clean the chamber and barrel everytime you pull out the reamer. I used a rod and patch and just pushed it out the end of the barrel each time. It needs to be clean everytime you reinsert the reamer. I oiled the reamer before putting it back in each time and some durring cutting. A cutting oil would probably be preferred but I used Hoppe's gun oil and a can of 3-in-1 oil. It can be hard to lower the reamer in with all that oil on it so be careful and don't drop it as you'll ruin the edge and maybe even the chamber. You have to reassemble the gun to check your headspace. You'll get good at it before you're done. Go slow when you are getting close. I figured out an easier way but I don't think I could describe it. I showed the gunsmith what I'd figured out and HE hadn't even thought of that and really rolled his eyes and grinned when I told him. It saved me a lot of time instead of a complete reassembly each time. Still, I took 5 1/2 hours to do this non-stop. I didn't want to lose the feel I keep talking about. You have to stop in a 4 thousanths gap to be properly headspaced. Go too far and you'll need a new barrel or a gunsmith. I had never even held a reamer before trying this so I know you can do it also. I probably have forgot something so feel free to ask. I still have to work out the loading issue. Rick
 
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