Chambering a 270 Winchester barrel for 7x57mm Mauser. Can or should it be done?

[corbinace]

So, I have access to a takeoff 270 barrel for minimal cost. I own a 7x57 reamer. I am thinking of making a Handi stub barrel in 7x57 rimmed.

The 7mm calls for a .284-5 bullet.
The 270 calls for a .277.

Another thought is that I could use a cut down 270 size die, neck size, and load with the smaller bullet and call it a 270 Rigby.

One thought on the different nomenclature is that it would likely never be shot/blown up after I leave this earth as nobody would have the correct cartridges for it. I am making it rimmed, so a normal 7x57 would not chamber.

What are your thoughts?

[Loudenboomer]

It's a little unclear to me what the question is?? Just don't send .284 bullets down a .277 bore!

[country gent]

How are you going to get the 7mm pilot into the 270 barrel??????

[405grain]

1. The 270 cartridge is longer than a 7x57, so unless you set the barrel back the chamber won't clean up. 2. The pilot of any 7mm reamer is not going to fit into the bore of a 270 barrel. 3. A .284" diameter bullet is not going to swage down and pass through a .277" barrel without causing significant pressure (and possible damage) to the firearm.

It would be infinitely better and easier to get a 7mm barrel blank and chamber it in 7x57. Buying a barrel in a caliber that its incompatible with what you are trying to do is what is called "Spilling dollars to pick up nickles". Also, having a reamer is fine, but you also need to have at least a GO gauge so that you can set headspace, a reamer holder, plus a barrel vise and an action wrench.

[challenger_i]

CorbinAce: pm sent.

[Jedman]

I have something similar. I took a 270 Win sizing die and shortened it by the difference in length between a 270 and a 7 x 57 R and while it was in the lathe chuck I used a dremel grinder with a small sanding drum to grind the ID of the shortened die back to its original diameter. Then using 7 x 57 R brass I could size it with this shortened die and it would just change the neck diameter and shoulder angle to that of a 270 Win.
Then I turned a 270 take off barrel to fit inside a 20 ga. barrel as a thick liner and being it was pre chambered to 270 Win. all I needed to do is shorten the breech end of the barrel - grind the ID a few thousands and cut a rim recess .
Jedman

[porthos]

i think you better leave things alone. you seem to be missing the basics.

[challenger_i]

I would bet dollars to doughnuts the OP is asking questions of the Forum so-as he may GAIN knowledge? Seems a logical step to me.

[corbinace]

Good Afternoon Gentlemen,

Thank you for all of the replies and advice to go with my brainstorming.

I really did a poor job of articulating what I was thinking about in my OP. I woke up with the idea and was kind of rumbling it around while I took a shower and ate breakfast. I decided to pose the question just before leaving to work on another project and should have waited until later when I had properly thought it through.

That said, you all brought up some great points and filled in a lot of the blanks.

This would be a Handi stub project and cutting the old 270 chamber down enough to make a new proper chamber was in the mix.

I am liking what Jedman has done. Utilizing the forward portion of the 270 chamber as is and blowing out the 7x57 brass loaded with a .277 projectile to fill the chamber. That also helps mitigate someone down the road putting a normal 7x57 in there and firing it.

All in all, a few hurdles to leap over and maybe not the absolute best path to pursue.

Thank you one and all for wandering down this trail with me.

[corbinace]

i think you better leave things alone. you seem to be missing the basics.

Yours is a new post while I was typing my previous response.

A very astute observation, but incomplete, as I am missing way more than the basics. As Challenger i points out, I am here to learn and see if I can fill in some of the many voids in my knowledge.

This forum and its members have been instrumental in helping me down many unlit paths to get to the light at the end.

I am much happier having you see my shortcomings and lack of knowledge, than to have you think of me as a "know it all". If that day comes, I hope you will tell me that too.

Thank you for your input.

[Milky Duck]

chamber it in the 7mm imposter/.284 rimmed case use said same dies BUT install a .270 /true7mm sized expander ball......
you could make neck/freebore a fly**** skinnier BUT many of us have loaded and used .308 calibre projectiles in a .311 bore AKA the 7.62x39mm forsure your brass life is slightly less but thats 3 thou vs 7 thou so not huge difference.
Ive often wondered if a 7mmrem mag with .270 sized barrel would excell..... now we getting faster twist .277 barrels its a moot point somewhat.

[brnomauser]

So in affect you’re thinking of making a 6.8x57? Cool idea, if you want one. It obviously won’t do anything a 7x57 or 270 won’t, but same is true of most cartridges. If you have the means then go for it, if you have to pay someone to do it then it’s not quite so attractive? So long as the chamber throat isn’t oversize I don’t think a 7x57 should chamber? Even if it it did I doubt the pressure would spoke to lethal levels swaging a 284 down to 277 at SAAMI 7x57 pressures

[K43]

It's been done and called .277 ICL Flying Saucer, 277x257 Roberts, and a couple of other variations.

[John Taylor]

I do handy guns often and my first question is which action are you going to use? If your planning on using the shotgun action it would not be a good idea. The SB2 action is is the one that is designed for higher pressure. The SB1 is usually good for anything that started life as a black powder round, keeping pressures down. Most of the conversions that customers want are in the low power pistol cartridges, 32 S&W, 9MM, 38 Special and a few others. When your talking 7X57 you get into high pressure, over 50,000 psi. Not something you want on an action that was designed for low pressure.

[JDHasty]

I was hoping this wasn’t going to be like the guy I worked with who told me his dad has a 30-06 “that also shoots 308 and 270, just not as accurately.”

Anyway, John Taylor is spot on on there being big differences in the strength of various Handi actions.

[John Taylor]

I was hoping this wasn’t going to be like the guy I worked with who told me his dad has a 30-06 “that also shoots 308 and 270, just not as accurately.”

Anyway, John Taylor is spot on on there being big differences in the strength of various Handi actions.

I don't think a 308 will fit in a 30-06 chamber without a little hammering. One of my in-laws hammered a bolt closed and destroyed a nice bolt action rifle. He was very lucky that the bolt did not come out but the mag box and stock were no more.

[M-Tecs]

I don't think a 308 will fit in a 30-06 chamber without a little hammering. One of my in-laws hammered a bolt closed and destroyed a nice bolt action rifle. He was very lucky that the bolt did not come out but the mag box and stock were no more.

John did you mean 270? A 308 fits and fires in a 30/06 chamber just fine. When I first started shooting NRA Highpower Service rifle the issued rifle was a M1 Garand with the so called 308 Navy sleeve. During the 200 rapid fire it throw the insert. At least 4 shots were fired without the insert with no apparent ill effects other than blowing out the shoulder of the brass. I was just starting so while the scores weren't great they were in my normal average.

https://www.cdvs.us/product/308-navy-sleeve/

[JDHasty]

John did you mean 270? A 308 fits and fires in a 30/06 chamber just fine. When I first started shooting NRA Highpower Service rifle the issued rifle was a M1 Garand with the so called 308 Navy sleeve. During the 200 rapid fire it throw the insert. At least 4 shots were fired without the insert with no apparent ill effects other than blowing out the shoulder of the brass. I was just starting so while the scores weren't great they were in my normal average.

https://www.cdvs.us/product/308-navy-sleeve/

My inclination when he told me that was that the rifle must have had a Mauser claw extractor and lots of excess headspace going on. Some folks I wouldn’t want to be on the next bench to at the range. ~ 1990 there was a guy with a couple pre 64 model 70 rifles at the next bench over. One in 308 and the other in 264 and he had ammo for both on the bench. I decided to leave early and thank God I did.

[John Taylor]

John did you mean 270? A 308 fits and fires in a 30/06 chamber just fine. When I first started shooting NRA Highpower Service rifle the issued rifle was a M1 Garand with the so called 308 Navy sleeve. During the 200 rapid fire it throw the insert. At least 4 shots were fired without the insert with no apparent ill effects other than blowing out the shoulder of the brass. I was just starting so while the scores weren't great they were in my normal average.

https://www.cdvs.us/product/308-navy-sleeve/

A civilian chamber is a bit tighter than a military chamber. I tried a 308 in three different 30-06 chambers and it only went into one, the other two would have required a little force to get the bolt to close ( a 2x4 maybe or a hammer.) I also remember the M1s in 308 with the white plastic block in the mag well. Boot camp 1966.

[405grain]

"This would be a Handi stub project and cutting the old 270 chamber down enough to make a new proper chamber was in the mix."

If the plan is to cut away the back of the barrel to shorten the chamber, that's not going to work. The locking mechanism on the bottom of the barrel needs to be able to mate with the action to lock the barrel in the closed position. Cutting away material from the breech end of the barrel is only going to create a big air gap between the barrel and the action. Is it even possible to set the barrel back on a Handi rifle?

[M-Tecs]

"This would be a Handi stub project and cutting the old 270 chamber down enough to make a new proper chamber was in the mix."

If the plan is to cut away the back of the barrel to shorten the chamber, that's not going to work. The locking mechanism on the bottom of the barrel needs to be able to mate with the action to lock the barrel in the closed position. Cutting away material from the breech end of the barrel is only going to create a big air gap between the barrel and the action. Is it even possible to set the barrel back on a Handi rifle?

OP stated it was a stub barrel so no issues setting a barrel back.

[Willbird]

For a break open gun IMHO you would want a rimmed case ??

Grafs does have 7x57R brass.

https://www.grafs.com/catalog/product/productId/74148

Bill