Rechamber 7x57 to 280 ackley???

[68lemans462]

I have a Ruger M77 in 7x57 which my grandfather gave me. This rifle just doesnt shoot as accurately as some of my other rifles, despite some considerable efforts with custom ammo. From what I have gathered, the accuracy problems could be due to the fact that this gun was chambered for 175 grain bullets, and I'm using mostly 139's (which are too far from the rifling)...

I was talking with my uncle and he said that this rifle can be rechambered in 280 REM or 280 ackley improved without too much trouble. Since this sounds like a viable solution, what are all of your thoughts on this matter? Also, any ideas what this "should" cost for a competent gunsmith to perform this work? Every one of my grandfathers rifles that I have shot (or own) is extremely accurate. I think he would be happy to see this done (if he was still alive) to the rifle, as long as accuracy is improved... Any input is appreciated... Thoughts?

 

[rule303]

It could certainly be done, but the chances of your local smith having a chambering reamer for .280, or .280AI are pretty slim. The M77's in 7x57 are known for having rather long throats. Are you handloading or using factory ammo? I have never seen one that wouldn't shoot halfway decent with the right load. 77's are picky about torque on the action screws, and like a little upward pressure on the barrel at the forend tip.

 

[Scooter22]

Well you could seat the 139gr. bullets out closer to the rifleing if the magazine will allow that and try them. IDK how old or what version you M77 is but it could be very collectable that a rechamber would ruin. Only othe thing I'm not sure of is are there 2 action lengths in the M77 line? You would need a "long" action to chamber a full lenth round like that. IDN if Ruger mad a medium action for the mid size rounds.

 

[Bwana John]

what are all of your thoughts on this matter?

Seat the bullets farther out?

The 7mm Mauser is intended for the bullet to be seated farther out than many US cartridge (same with 8mm Mauser, it was a way to increase velocity without raising pressure)

Have you tryed 175 gr?

A slightly quicker twist rate should have very little affect on the lighter bullets.

 

[68lemans462]

I'm using 100% handloads mostly using 139 grain bullets and loads with H414/4350... I've tried several bullet seating depths, many that are LONG... I have not tried 175's yet, but I am willing to!

If I can find a smith with the reamer, what would be a reasonable cost? This one does shoot half way decent, but I want it to shoot better than that!

Can you tell more about the torque action on the screws you mention?

 

[headoftheholler]

Before going to something else, the 175's should be at least attempted, the 7x57 is one hell of a round with the heavier bullets on even larger game.

 

[morcey2]

If the rifle isn't shooting as well as you like, rechambering it will only solve the problem if the issue is the throat AND the new chamber takes out enough of the bad throat to solve the issue. Minimizing bullet jump won't make an inaccurate rifle accurate, but is more of a fine-tuning issue on an accurate rifle.

Odds are that the excessive bullet jump isn't the issue. Eliminate the easy stuff first. Crown, scope mounting, trigger, action screw torque. Then move on to glass/pillar bedding and more involved fixes. If you rechamber without accurizing the rifle first, you'll probably have the same inaccurate rifle but with more recoil and velocity.

When you say that the rifle isn't as accurate as your other rifles, what kind of groups are you getting? I've got 2 7x57 rifles, both military surplus rifles that have been customized, but retain the military barrel with the extremely long throat for 175 gr round-nose bullets. They both shoot great with 110, 120, and 139/140gr loads seated no-where near the lands.

And, if you really have a 68 LeMans with a 462 in it, please tell me it's based of the poncho 455 and not a bowtie engine.

Matt

 

[rcmodel]

Have you considered it might just be the barrel won't shoot, and it has nothing to do with the throat?

Ruger M77 barrels of that time were often as not, Not.

So paying good money to re-chamber it, only to find out it still won't shoot would be a real bummer!

The first thing you Have to do is test it with heavy bullets.
If that makes no difference?

Don't waste your money re-chambering it.
Put the money toward a new high-quality barrel, and not one in .280 Ackley either!

rc

 

[Kp321]

+1 on rc's comments. Ruger barrels were very iffy those days and some just did not shoot. I have a 280 Rem and AI reamers and would do the job for around $100 but like rc said, there is no guarantee it would help. Rebarrel with a premium barrel in 7x57, bed it properly and all your problems should be solved.

 

[denton]

If you rechamber without accurizing the rifle first, you'll probably have the same inaccurate rifle but with more recoil and velocity.

Exactly.

Diagnose your rifle before prescribing a cure.

 

[Bwana John]

The provenance of the 7mm Mauser cartridge beats out ~150fps gain of velocity as far as I am concerned.

Every time I shoot mine I get visions of Bell using it on Jumbos, Boers using it @ 600 yds on Khakis, and Spanish mowing down Rough Riders...

Ackley was a Fudd.

 

[Vern Humphrey]

Is this an old shotgun safety style M77?

Most of those were made when Ruger contracted out its barrels, and you can get some sorry barrels. If it were my rifle, I wouldn't waste money rechambering it --that will do nothing to enhance accuracy, anyway.

If things like tightening screws, glass bedding and free floating, plus careful load development won't give you the accuracy you want, I'd go straight for a new barrel.

 

[68lemans462]

Great suggestions guys! The rifle has been glass bedded, although the trigger does leave something to be desired. I'll try some heavier bullets with it and see if results improve. If not, I might consider re-barreling at some point.

Any more information on this torque screw that keeps getting mentioned? Thanks..

 

[rcmodel]

Talking about the guard screws that hold the rifle in the stock.

If you don't have a torque wrench?

Tighten the front angled screw TIGHT.
Then tighten the rear screw tight.
Then tighten the center screw just enough to keep from springing the trigger guard and keeping the floor-plate from latching shut.

Best description I have seen was on another forum.

1-Front angle screw "Gorilla" tight
2-Rear action screw "Chimpanze tight.
3-Middle action screw "Organ Grinder Monkey tight"

rc

 

[morcey2]

Great suggestions guys! The rifle has been glass bedded, although the trigger does leave something to be desired. I'll try some heavier bullets with it and see if results improve. If not, I might consider re-barreling at some point.

Any more information on this torque screw that keeps getting mentioned? Thanks..

The action screws should be torqued to somewhere between 30 and 75 inch/lbs, depending on the stock material and bedding. On my mausers and springfields that have been glass- and pillar-bedded I torque to 60 in/lbs. You can get a click type torque driver from Wheeler for about $60:

http://www.midwayusa.com/product/71...m-accurizing-torque-torque-wrench-screwdriver

I use mine all of the time.

A couple other questions:

What kind of groups are you getting and what type of spread are you getting? i.e. vertical stringing, impact moves up and to the right as the barrel warms, looks like someone shot the target with buckshot at 30 yards.

Have you tried a different scope? (if it's a scoped rifle)

Does it behave the same for other people when they shoot it?

Weight and recoil-wise, is this gun similar to the other guns you shoot that shoot better? I've seen a couple of cases where a person shooting a lighter rifle, even with a lighter-recoiling round, develops a flinch with just that rifle.

Matt

 

[Liberty1776]

Best description I have seen was on another forum.
Quote:
1-Front angle screw "Gorilla" tight
2-Rear action screw "Chimpanze tight.
3-Middle action screw "Organ Grinder Monkey tight"

dude, that's awsome advice, and describes it perfectly...

 

[Uncle Grinch]

I had my Interarms Mark X in 7x57 rechambered to 280 Rem about 20 years ago and have regretted it ever since. It shot good as a 7x57 and still shoots good as a 280 Rem, but the difference is not noticable downrange, since I reload. Last year I contracted for a custom 7x57 built by Mike McCabe (z1r). To be honest, this is more of a personal, i.e. emotional thing since I liked my 7x57 so much.

You may contacxt E.R. Shaw and just have your Ruger rebarreled to another 7x57 or to 280.