Anyone ever convert a 375BB to 307?

handirifle · Post by **handirifle** » Sun Sep 09, 2012 11:51 pm

Kinda wondering out loud about converting the 375 BB to a 307 to make it more practical to hunt with. Anyone ever done this? Who did it for ya? Cost?

Streetstar · Post by **Streetstar** » Mon Sep 10, 2012 12:05 am

It would cost about half of what it would cost to procure a 307 to hunt with without messing up the 375 --- seriously, why not sell the 375 and use the proceeds to buy a 307 ?

Or go on Ramen and ham 'n cheese for a few weeks and add another rifle to the stable !

handirifle · Post by **handirifle** » Mon Sep 10, 2012 12:17 am

Well I inherited the gun, and due to the stupid lead ban it's hard to hunt with. Making the bullets is a real PITA, and they are ready made for the 30-30 (Barnes TSX flat nose 150gr) and those would work well in a 307. That way I would still be using the gun, sort of.

If I just wanted to use another gun, I'd use my bolt gun. Like I said, I was wondering out loud. Who does the work?

AJMD429 · Post by **AJMD429** » Mon Sep 10, 2012 12:27 am

I don't know about the conversion, but no doubt someone on the forum will pipe up in due time with an answer on that.

Food for thought in the meantime. . . I've seen people load .308 and .358 bullets in not only .50 caliber, but .45 and .40 caliber rounds using sabots; never saw a .358-in-.375 sabot though. It would be a nice way to use a fine gun and maybe get around the stupid lead-ban laws. I even used the .223-in-.308 ones to make home-brew 'accellerator' loads a few years back.

MMP Sabots are fun to play with though - here's their .312 in '36 caliber' one, but I don't know the actual diameter of a .36 muzzleloader. http://www.mmpsabots.com/grey1.html

(MidwayUSA sells some "36 caliber muzzleloading bullets" that are .375" though, so maybe you actually could load up some lesser-caliber Barnes 'solids' in sabots and use that .375 BB...

)

Streetstar · Post by **Streetstar** » Mon Sep 10, 2012 12:51 am

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handirifle · Post by **handirifle** » Mon Sep 10, 2012 12:56 am

My personal experience with sabots has not been a happy one.

C. Cash · Post by **C. Cash** » Mon Sep 10, 2012 7:39 am

The 307 uses the bigger diameter threads/barrel, so don't believe you could interchange a barrel. The 356 and 444 also have the bigger diameter. I think the added steel is a good idea with a potential 52K cartridge, though folks like Myron Rockett have done it with no problems. I would save for a 307 myself, or the 356 cousin.

Marc · Post by **Marc** » Mon Sep 10, 2012 8:54 am

The 375 uses the large threads too. Numrich has the barrel:http://www.gunpartscorp.com/catalog/Det ... catid=7512. The barrels are Angle Eject and your 375 is probably top eject so a new extractor slot would have to be cut. That can be done with a hacksaw and file. All you need then is somebody to unscrew the old one and screw in the new one. You could probably do it yourself.

The feed guides would also have to be widened since a 307 case is fatter than the 375 case. Again a file will take care of that. If you were close I would help you with it.

C. Cash · Post by **C. Cash** » Mon Sep 10, 2012 9:25 am

There you go....I stand corrected.

Malamute · Post by **Malamute** » Mon Sep 10, 2012 10:09 am

Marc pretty well summed it up. Buy a barrel before they disapear, and either do it yourself or have a gunsmith do it. Last one I had a gunsmith swap cost $15 for a simple swap. That was handing him just the barreled action and other barrel. Winchester barrels aren't hard to change. Be sure you strip the bolt out of it (or be sure it's open), and any screws that your receiver fixture/vise/wrench may contact.

If your gun is the XTR model, Numrich has both standard and XTR barrels in that and 356 cal. Heck, get a 307 and a 356 barrel in case you want to have one of those some day.

BenT · Post by **BenT** » Mon Sep 10, 2012 8:27 pm

I have used the big bore barrels from Numrich. They had both with front ramp and dovetail. It's no big deal swapping them out even if you need an extractor cut.

handirifle · Post by **handirifle** » Tue Sep 11, 2012 9:41 pm

Great! Thanks for the info, glad I asked. Might be easier than I thought.

handirifle · Post by **handirifle** » Tue Sep 11, 2012 10:06 pm

Got a 307 barrel on order. Might order a 356 barrel later, no funds left for now. $66 after shipping.

What about setting headspace? Several of you mentioned just screwing the barrel in but no mention of that, and also did the sights line up or what?

Malamute · Post by **Malamute** » Tue Sep 11, 2012 11:17 pm

You can measure the barrel with a caliper to get the distance from the rear of the barrel where the rim touches when a round is chambered, to the shoulder that bears against the front of the receiver. You can then measure from the front of the receiver to the bolt face when it's closed, then subtract the barrel mesurement and get an actual headspace number. Comparing the old barrel to the new may be interesting, just to see what they set it up at the factory.

They headspace on the rim, a 30-30 headspace gauge should work, if you want to use a gauge, but measuring will give you a real number, rather than if its just within a range of numbers, and therefore "in spec" but an unknown figure. Dont use a cartridge as a headspace gauge, unless you figure in the dimensions of the exact round your using (most descriptions of how to check headspace with a cartridge and shim material or plastigauge leave out the rim thickness number, then you have meaningless info without it)they are usually a bit undersize from exact spec, and they can vary. Thats the reason the spec has a range of acceptable sizes. They can be all over the place.

Most seem to index pretty well. The ones I've done have headspaced fine so far as I can tell, not had any problems.

handirifle · Post by **handirifle** » Tue Sep 11, 2012 11:58 pm

OK good idea on the measurements. I was aware they headspace on the rim, but since no one mentioned it I had to ask. I have swapped barrels on my savage rifles many times, and understand headspacing them as well. Those are a bit different than the levers though.

Are any special tools needed to unscrew the barrel on the Winchester?

BenT · Post by **BenT** » Wed Sep 12, 2012 7:00 am

You need a barrel vise and action wrench. An action wrench can be made from flat stock, but a good barrel vise is needed for some of the Winchesters I've done. All of the factory barrels I have done head space just fine.One I had to really tighten to get it headspace, but no lathe work was needed. You can tell if you are in the range , because the face of the barrel should be flush with the inside of the receiver. Take a look at yours and you will see what I mean.

handirifle · Post by **handirifle** » Wed Sep 12, 2012 9:53 am

OK thanks. What barrel vice did you use? For my Savages I use an action vice and barrel nut wrench, some use the barrel vice, but never needed one. I will probably make one up though, for this. What material is best to "grip" the barrel? Wood?

Marc · Post by **Marc** » Wed Sep 12, 2012 12:51 pm

I use maple blocks with a little rosin sprinkled on them to hold the barrel. I made the vise from two 1" steel plates with four 1/2" bolts to clamp the blocks. My action wrench is a length of 3/4" square bar with a 1/2" x 3/4" strap. I used two 5/16" bolts to clamp the receiver in the wrench. Masking tape on the "jaws".

I have only swapped one 94 barrel and it indexed and headspaced fine. A friend has done a bunch of them and he says they headspaced fine. Not a difficult job at all.

BenT · Post by **BenT** » Wed Sep 12, 2012 5:50 pm

Made my action wrench and vise out of 1/4 x 2 in wide steel stock. I made my block out of hardwood using a hole saw and then cutting it in half. Barrel vise has one side flat stock at 8 inches and the other at 5. With 3 1/2 bolts to sandwich blocks and barrel in. The longer end of flat stock is secured in the vise on my bench to hold the barrel vise. The action wrench has a 18 in piece and 6 inch piece to sandwich the action in ,with cardboard for keeping the action from getting scratched. the long end is your handle.

hammerman · Post by **hammerman** » Wed Sep 12, 2012 6:11 pm

I had this very same conversion done on my 375, except it was made into a 356. It will be the same on the 307.

I bought a 356 gun barrel, 356 cartridge guides, and AE 356 front and rear barrel bands from gun parts corp. The new guides were put in, the forearm had to be sanded out for the bigger barrel, and the new barrel was installed after the old one was taken off. Barrel bands were changed as well because of the bigger barrel. A new extractor slot had to be cut into the barrel as well. This is a fairly straight forward conversion and I had Mic McPherson do the work for me. The reason I did mine was because I'm a traditionalist and I wanted a top eject, non-rebounding hammer 356.

tman · Post by **tman** » Wed Sep 12, 2012 6:31 pm

hammerman wrote:I had this very same conversion done on my 375, except it was made into a 356. It will be the same on the 307.

I bought a 356 gun barrel, 356 cartridge guides, and AE 356 front and rear barrel bands from gun parts corp. The new guides were put in, the forearm had to be sanded out for the bigger barrel, and the new barrel was installed after the old one was taken off. Barrel bands were changed as well because of the bigger barrel. A new extractor slot had to be cut into the barrel as well. This is a fairly straight forward conversion and I had Mic McPherson do the work for me. The reason I did mine was because I'm a traditionalist and I wanted a top eject, non-rebounding hammer 356.

Top eject, non-rebounding hammer 356WCF. WAY

. If you get tired of it, let me Know

handirifle · Post by **handirifle** » Wed Sep 12, 2012 10:05 pm

Great info. This brings more questions to mind, things I had not thought of before. Seems odd that the 356 barrel was bigger than 375, how did you know ahead of time, or did you?

How far from the reciever do you clamp the barrel?

It would seem certain the receiver wrench need only be tight enough to prevent slipping. Would it be easy to over tighten and bend the receiver?

How tight are the barrels, usually? I know some of the barrel nuts on factory Savage rifles are like a gorilla tightened them.

I have some steel that ought to make a nice action wrench, will need to make a barrel vice though. Can that be flat stock and the hole cut into just the wood? Seems I read one of the responses, where that was the case.

Malamute · Post by **Malamute** » Wed Sep 12, 2012 10:55 pm

You want to grab the barrel as close to the receiver as is practical.

The topic came up in the past ony the terms were reversed. I managed to find a good picture of a barrel wench though. (note spelling)

Hardwood blocks can be used on some, and they are sometimes rosined to get a good grip and avoid slipping. Powdered rosin I believe, probably available from music stores, but I'm not sure. Brownells may have soemthing also. Aluminum blocks work too. Boring a hole as close to the barrel size where you want to grab it, them splitting it with a saw should work.

BenT · Post by **BenT** » Thu Sep 13, 2012 7:10 am

Since it's a flat sided receiver , the action wrench just needs to be good and snug so it doesn't slip ,not reefed down. The barrel vise with the wood blocks need to be as tight as you can make them, that is where it will slip. The advise I was given by a gunsmith for breaking loose the barrel and it works. Was to get a 5lb mechanics hammer, the plastic one full of lead shot.
When you have the barrel vise secured, bolted to a table or in a vise. Have the handle of your action handle straight , grab your hammer and swing it like a bat and connect with the handle. A solid blow will break the barrel free easier than the prying on the handle. I've found that this works for me. I have had stuck barrels on 94's that I had to use my friends commercialy made barrel vise to keep the barrel from slipping.

I leave the bolt in the receiver but back about an inch to make sure that the extractor isn't in the end of the barrel. This keeps the receiver from flexing when clamping on the action vise.

Also on Savages I take a heatgun to the barrel nut, to loosen up the locking compound they use. It makes a big difference.

Marc · Post by **Marc** » Thu Sep 13, 2012 8:05 am

All of the several lever action barrels I have removed came off easily. None were as tight as the typical bolt action barrel.

I keep the receiver wrench as close to the front of the action as possible. That way the wrench is over the solid webs inside the receiver. Sporting goods stores have rosin. Weight lifters use it.

The barrel vise is just flat stock. Bore the hole in the wood block.

hammerman · Post by **hammerman** » Thu Sep 13, 2012 4:32 pm

handirifle wrote:Great info. This brings more questions to mind, things I had not thought of before. Seems odd that the 356 barrel was bigger than 375, how did you know ahead of time, or did you?

How far from the reciever do you clamp the barrel?

It would seem certain the receiver wrench need only be tight enough to prevent slipping. Would it be easy to over tighten and bend the receiver?

How tight are the barrels, usually? I know some of the barrel nuts on factory Savage rifles are like a gorilla tightened them.

I have some steel that ought to make a nice action wrench, will need to make a barrel vice though. Can that be flat stock and the hole cut into just the wood? Seems I read one of the responses, where that was the case.

For some reason I knew that the ae bigbores had bigger barrels from previous research. I don't remember any specs on the barrel removal, but the advice from above seems right.

handirifle · Post by **handirifle** » Sat Sep 15, 2012 1:40 am

Thanks guys, will let you know how it goes when I get ready to swap them out. Right after I ordered the barrel, I cracked the upper limb on my Mathews bow (

PLEASE don't ask). Am not the original owner, so no warranty. I will have to replace that before I can go any further on the levergun project.

BenT · Post by **BenT** » Sat Sep 15, 2012 8:15 am

Ouch ! that will set you back. They are great guys and do have a very nice shop. Have you called them about it. I always start out by saying that, I broke your product. Take the blame and they usually are more helpful.

handirifle · Post by **handirifle** » Sat Sep 15, 2012 12:08 pm

Well I haven't talked to them on the phone. I shot off an email to them, but haven't heard back yet. I did call the "local" Mathews dealer (45 miles one way) and he was pretty gentle, says $85 plus about $15 to install. I just have to wait till I have the funds now, being retired and all.

Kinda a good thing I ordered the barrel when I did or else the money would have gone to the bow.

handirifle · Post by **handirifle** » Wed Sep 19, 2012 4:51 pm

OK my barrel arrived today, looks great. At first, I thought, this thing is a MESS, but then figured out it was covered with some sort of protection to keep it from rusting. I need to look around for some brass to try, guess I'll look at fleabay.

Will see how it cycles, or not, and go from there.

Hey, does 308 brass work in these? Seems I have read that before.

handirifle · Post by **handirifle** » Thu Sep 20, 2012 1:04 am

Ok I checked a few things today. First, the .375 barrel is about .610" dia just behind the front sight, where the barrel band goes, and the 307 barrel, measures .725". That seems backwards to me, the smaller caliber barrel is larger in diameter??? Sooooo that means new bands for sure. I also took a 308 case and stuck it in the new chamber, and it seats what appears to be perfectly to me. It leaves the "V" right above the base, exposed for the extractor to grab.

Next I slid the same case into the receiver and TRIED to cycle it. Not happening! If fact it got stuck coming about halfway out and took some doing to get it back out. So I guess the receiver parts need to ordered as well.

Hammerman
Is there a left hand and right hand cartridge guide?

Numrich's doesn't list the barrel bands, any idea who else carries them?

hayabusa · Post by **hayabusa** » Thu Sep 20, 2012 1:05 am

It works in mine.

busa

handirifle · Post by **handirifle** » Thu Sep 20, 2012 1:33 am

hayabusa wrote:It works in mine.

busa

You're saying the 308 brass works in your 307?

hayabusa · Post by **hayabusa** » Sat Sep 22, 2012 2:55 am

Yes, it works in my Marlin. The gunsmith rechambered it & slimmed the forearm like a Winchester. I loaded it with .308 brass and Speer 150 grain round nose bullets. It cycles fine.

Fellows I must be having a dumb moment. My Marlin was a 30-30 originally and rechambered to 307 Winchester not a 375 to 307. My mistake!!

Maybe I need to go to sleep. Lol

busa

handirifle · Post by **handirifle** » Sat Sep 22, 2012 7:16 am

Not a prob Busa. The rim of the thuty thuty is slightly wider than the 375 and maybe that is the difference.

Now I need to find out if I need one loading gate or 2, I am guessing I need 2, a left and right.

BenT · Post by **BenT** » Sat Sep 22, 2012 9:13 am

http://www.winchesterguns.com/customers ... s-info.asp

Go to this site and go to the bottom and select please continue and download the 2008 parts catalog. It will show the left and right cartridge guide part numbers. I have ordered parts from there since Winchester closed their doors. That was a couple of years ago and they still had parts.

Malamute · Post by **Malamute** » Sat Sep 22, 2012 1:25 pm

It's probaly the body, not the rim that wont fit thru the guides. the 307/356 is a thicker base then any of the 38-55/30-30 based rounds.

handirifle · Post by **handirifle** » Sat Sep 22, 2012 3:46 pm

Ben
thanks for the link, I will go through it.
Malmute
That was what I was thinking too, it seemed like the body didn't want to come through.

handirifle · Post by **handirifle** » Sat Sep 22, 2012 3:50 pm

Wow, I looked through a little, and IF they have them in stock, the guides are half of what Numrich's wanted. Cool.

handirifle · Post by **handirifle** » Sun Sep 23, 2012 5:02 pm

Hammerman
do you recall if the band screws also had to be replaced? Are they longer than the others?

BenT · Post by **BenT** » Sun Sep 23, 2012 7:16 pm

I just measured my 307 compared to my 30-30 and the 307 screw is about 1/8 in longer.

handirifle · Post by **handirifle** » Sun Sep 23, 2012 10:31 pm

I assume, they are both flush when mounted as well?

1894c · Post by **1894c** » Mon Sep 24, 2012 1:44 am

great thread..great info...thanks guys... :)

handirifle · Post by **handirifle** » Mon Sep 24, 2012 11:39 am

336bl wrote:great thread..great info...thanks guys...

Welcome!
Hey with all this "switch barrel" info, I feel like I am over at savage shooters.com

. This is everyday conversation over there. I'm glad it's not as difficult as I was afraid it was going to be. The hard part, for me is going to be acquiring all the parts, THEN gettin the gumption up to make the swap. That Big Bore receiver, just gleams, and I will kick myself HARD if I scratch it.

hammerman · Post by **hammerman** » Sat Sep 29, 2012 11:34 am

I just got back from hunting.

I don't remember having to change the barrel band screws on my conversion. The cartridge guides do have a left and right. I did order the barrel bands from gun parts corp., but I think I had to call them and tell them what I wanted. Let me know if you have anymore questions.