Grrr, cut too deep

[bruce drake]

I went to chamber a new 260 Remington on a Yugo 48 Mauser this week and I cut the chamber a little too far.

I used my 308 Win Go and No Go guages and I knew I cut too deep once I stopped and slid the headspace gauges in with no resistance when I closed the bolt. Thinking I might still be within Field Specs, I built a couple of COW loads with some Unique powder to form the cases so I could tell how far I actually cut.

After fire-forming and measuring the blown out cases it looks like this rifle going to have to go back on the bench and be rechambered to 6.5x55 or 6.5x257 Roberts in January.

I'm thinking 6.5x257 due to brass availability as I hate to pay new for 6.5x55 Swede cases when I can use my current 7mm Mauser brass stocks or reform cutdown -06 cases. The dies are more expensive but the price of brass would definitely offset it and the cartridge will do everything the 6.5x55 Swede case can do.

This has been my first error in chambering a barrel, but I hate knowing my perfect record is gone.

As a home gunsmith, at least the customer (me) didn't freak out when he found out. :)

Bruce

[theperfessor]

Dumb question maybe, but is there any way to set it back one thread and recut the chamber?

[hornsurgeon]

best idea is to shorten the shank, move back the sholder, and recut the chamber. that is, unless you don't have access to a lathe. other wise, i'm sure someone here could do the lathe work for you.

[bruce drake]

Taking the rifle in to get the threads reset at the local gunsmith would cost more than my renting another set of reamers and buying another die set. And I am a heck of a lot faster to complete the project than my local gunsmith.

I'm already set up to spin on and take off Mauser barrels and normally I measure twice and cut once but I got distracted at the last moment when my wife came into the mancave as I was cutting the chamber. Not her fault. I should have pulled the cutter off the barrel when she came in and then flushed the chamber, checked the cut and started fresh after she left.

I posted this as a Mea Culpa event so others could learn from my error as well.

Bruce

[theperfessor]

Mea culpa, I assumed you had used a lathe for chambering. Don't really think you can go too wrong with any caliber that's based on the 7mm/8mm x 57 case. Have you thought about an AI chambering?

[bruce drake]

I'm sticking with standard chambers for now. A little easier to feed them when you can easily find or make the cases.

6.5x57 has been a European chambering for a long time so I should be able to use that data or at least 260 REM/6.5x55 data to start.

Just primarily angry with myself. 20 rechambers (I use a logbook) done correctly over the last few years and then I blow this one badly. I already have a 260 Rem chambered rifle but this one was going to be a Long-Range Match rifle for 1000 yard matches.

Bruce

[theperfessor]

Yeah, I know that pit of the stomach feeling that comes from screwing up a machining job. Well, no matter how good you are there will always be days like that...

[Casting Timmy]

This has my curiousity risen, so how are you cutting the chamber?

[largom]

This has my curiousity risen, so how are you cutting the chamber?

Same here. Do you have a lathe?

[deltaenterprizes]

Curious also, why not measure how much too deep the chamber is and set the barrel back.
Tin foil is .001'', stack small pieces until you feel resistance on the bolt closing.

Do you use short chambered barrels and then finish the chamber by hand?

[Mk42gunner]

Bruce,

There might be a problem with reaming the chamber to 6.5x257, the shoulder of the .260 case may be too big to totally clean up. I was going to buy a short chambered .260 barrel and ream it to 6.5-06 and one of the techs at Brownells advised against it, because of that issue.

If it is just a little too long, you could mark the barrel .264 BD and have your own wildcat. You might still have to make the brass from something longer than a .308 though.

Robert

[Pepe Ray]

Hi Bruce from Piscataquis County.

Here's what I'd do, K.I.S.S.
Treat the chamber as a wild cat. Reload as required.
I.D./Stamp the bbl with a new monica. Enjoy.

Think about it.
Pepe Ray

[bruce drake]

Unfortunately, no lathe.

I use short-chambered barrels usually but I did once (and only once) chamber a threaded barrel blank for a 308 Winchester by hand with a rough and finish chamber reamer set.

I use a T-handle extension and turn the reamer by hand. Depending on the depth of cut needed I may chuck the extension rod itself in a drill for the majority of the cut. I lube heavily with cutting fluid to help prevent chatter.

Right now, the case blows the shoulder out forward to roughly .456 in diameter at the end of the cartridge's body with the length going to 1.665" for the case body before the shoulder sarted to form into the neck. Right now the cases look like a 260REM AI with a very short neck.

Its a custom chamber right now...I'm not looking to replicate it again... Right now, 264 Win Mag, 6.5 Rem Mag and 6.5-284 Winchester are the cartridges that are feasible options to recut for. I just need to decide what will the next chamber be now.

Bruce

[Mk42gunner]

Will the .264 fit in the magazine? I can't remember which of the 48 Yugo's were the shorter action.

With either of the Magnums, you wil have to open the bolt face up to fit.

The 6.5x284 sounds like a good choice for this gun; 1. the case head will fit the bolt. 2. the reamer should clean up the chamber. 3. the loaded round should fit in the magazine. and 4. there is a good chance the rounds will feed without too much extra work to the feed rails.

Robert

[bruce drake]

I've been looking and thinking about the 6.5x284 cartridge as well today while puttering around the house doing winter chores.

You pegged the four primary reasons why the new cartridge will probably be 6.5-284. The fifth reason is that the cases would last a lot longer than the rimmed cartridges for reloads as well.

I did form a duplicate of the blown-out case today with a 308 Win case expanded to 358 Win and I then reformed the neck down with a 260 Rem Size die to form the short neck like the blown-out case. So at this point I had a case almost like the blownout case. I then took the case out and did a COW/Unique shot into the air which formed the case to almost exactly like like the original blown-out case. So at this point I have a couple of fire-formed cases to check for function later this week.

Now, its nice to see I now have a custom .264 BD chambered rifle but I doubt with several other rifles to choose from, I won't stick with the new "custom" chamber but instead will go with a complete rechambering. Besides I have to get back on my chambering average. 95% good isn't good enough. I need to raise the percentages back up again.

Bruce

[JIMinPHX]

I've cut a chamber too deep before. I fixed it by turning the shoulder & the face back a little bit & then turning the barrel into the receiver another 1/4 turn. Since I had not cut the dovetails for the sights yet, I was able to do just 1/4 turn, rather than a full turn. Making the two cuts on a lathe took less than 15 minutes, including set up time. Most local machine shops should be able to handle something like that for reasonable money. It's an easy job.

[bruce drake]

I called around and a friend of mine (an Allied Trades Warrant Officer (basically a super-Machinist)) who just recently retired from the military has a lathe and he's willing to recut the shoulder and face for me. Its going to be a 4 hour round trip but the time spent with him will be worth the gas and time. Now I just need to get the time to spend the day driving to see him around all the family holiday committments we both already have to deal with.

Bruce

[Hip's Ax]

Hey Bruce, I have not done a ton of 1000 yard yet, a few matches a year. I have been using a 260 and while it hammers at 600 you must really watch the wind at 1000 compared to a 6.5-284. Of course the 1000 round life expectancy of the 6.5-284 is something to consider as 260's last 2000+ I was assured that the 6.5-284 shoots so much better at 1000 it is the way to go. Wish I could personally verify this to you but I have not yet had my 6.5-284 to the 1000 yard line except for zeroing.

[bruce drake]

Barrel life was one of the reasons why I originally chose 260 Rem over 6.5-284 but I've been shooting 308 Win for several years at 1000 and if I can loosen a few inches of clicks off my windage with the 260 over the 308 will be a plus in the windier days.

I've visiting family in the Midwest for the next couple of days so pulling that barrel will have to wait for a few days or so before I can get it down to the smith for redoing the shoulder and threads.

Bruce

[felix]

Bruce, barrel life should be about the same, based upon the amount-of-powder/bore-size. I would go with the 6.5 over the 6.0 if range is more important than trajectory to you. ... felix

[gunguychuck]

Why do think you ruined the chamber. Just measure how much farther to screw the barrel in. Most prethreaded and chambered barrels come with a chamber .010 to deep. It is a simple matter to headspace the barrel to the action.

[bruce drake]

Well, I dusted off this project for a little bit last night with a little bit of Internet Research.

There is a 6.5-257AI Wildcat that would clean this chamber up and keep the cartridge length within the M48 action limits. I'll be renting the reamer sometime this week and we'll see what a few twists of the reamer does to clean up the chamber. I've got a ton of 30-06 and 8mm cases that I can reform to the cartridge as well. The cases will have to be fireformed with some Unique and some Lead Boolits to blow the shoulder out but it will get the barrel shooting again.

The RCBS dies new cost more than the barrel did so I'll use the reamer to also cut an old (spare) 6.5 Jap resizing die to match.

So... the NRA long range rifle project continues.

Bruce

[garandsrus]

Bruce,

Aren't the sizing dies hardened? If they are, I don't think a reamer will be able to cut it without first annealing the die.

John

[flounderman]

I have a 6.5-284 and I am going to have to break down the loaded cases I have and anneal them. necks are splitting and it's new brass. also 284 brass isn't that common compared to 243. I have hunted with a 260 with a model 7 barrel the last two years and I like the caliber.

[bruce drake]

Well, If it doesn't work I still have the 260 Rem sizing dies to seat the bullets.

Chucking dies in lathes to cut custom sizers has been done before so it should work. It will be the first thing I cut with the reamer and the company says they do it all the time when they do custom die sets.

Bruce

[bruce drake]

Here is a picture of a 6.5x257 Roberts cartridge and two of my fireformed and blown-out 260 Rem cases (note the cracks in the case body) compared to a standard 260 Rem cartridge (all are dummy rounds).

What I am planning to do is to make the chamber a 6.5x57AI which will blow the shoulder forward to the neck at a 40deg slope. This will basically take the 6.5x257 Roberts case with its sloping case taper and fireform the case into a straighter taper like the 260 Rem has while moving the chamber length forward 6mm.

I've ordered the reamer and with this short of a cut it will all be done by hand so the chance of my overcutting the chamber this time will be a lot slimmer (and I also will do it while wife and kids are away so I don't get distracted...)

Now for those reloading snobs who will look at the picture and say there are wrinkles in the shoulder of the 6.5x257R case, well you are right. I just lubed up the 8mm case and ran it up the 257 sizing die and then used a 260 Rem Sizing die to open the neck of the case up to allow a 140gr 6.5 bullet to be seated into the dummy round with a 260 Rem seater die.

After I recut the chamber, in the absence of the $140 RCBS dies from MidwayUSA, I will use the 260Rem Sizer to resize the neck of the parent 7mm Mauser case and then blow the shoulders forward with a fireforming charge and a 140gr lead boolit. After they are fireformed, I'll necksize them for all future reloads until I can get a Sizing die recut to match or have LEE make me a custom necksizing die set ($60 with a 2-6 month production time) off my fireformed dummy cases.

Well there are small steps but this rifle will get shooting again...

Bruce

[hickstick_10]

Bruce,

Aren't the sizing dies hardened? If they are, I don't think a reamer will be able to cut it without first annealing the die.

John

I was thinking the same, if they are your reamer will be ruined.

[bruce drake]

you guys are right on the reamer in the sizing die. I called PTG dies in OR and they confirmed that.

[Dark Helmet]

Which is, I beleive, done with a 6.5 Gibbs reamer run in short.
Shorten 6.5 Gibbs dies and you are done.

[bruce drake]

6.5 Gibbs -- That's about what the shoulder is supposed to look like. With the M48 Intermediate-length Action, I need to keep the cartridge length at 57mm or shorter for proper feeding from the magazine.

The reamer and headspace gauges should be in my mailbox by Monday so hopefully I'll cut the chamber by Tuesday and get some ammo loaded and shot by next weekend.

Bruce

[bruce drake]

The Reamer Rental Shop just called this evening and I'm on backorder. The previous renter jacked the reamer up by dropping it on a concrete floor and they have to make another one before I can cut the chamber.

So... the project continues but with a little delay.

Bruce

[Dark Helmet]

Look here for some Mini coop info-it's on the 6mm Rem. or 7x57 RWS case

http://specialtypistols.infopop.cc/eve/forums/a/tpc/f/7936077864/m/517102194?r=895102494#895102494

[bruce drake]

RCBS 6.5 Gibbs dies cost the same as the actual RCBS 6.5x257 AI dies.

Bruce

[Dark Helmet]

Hornady Custom Shop or a neck sizer only maybe? 6.5x257 dies would work if you didn't bump the shoulder, have seen them for sale used.

[leadman]

A couple of the companies sell blank dies. IIRC there was a blank die listed on the Midway site. I think there was an ad in the Handloader mag also.
You could call Lee and ask if they will sell you a blank.
Just looked in the Midway catalog and they list a Callahan do it yourself die blank with pilot hole for $24.99, without PH for $16.29. You can use the reamer on this. Part number for piloted 6.5 is 786-397. This is 7/8 thread to fit a reloading press.

[Mk42gunner]

The problem with using a chamber reamer to make a set of dies with is that the neck portion of the die will be the same size as the chamber; thus no resizing. I thought about this when I was making a 6mm-300WSM.

IIRC Roy Dunlap recommended using a roughing reamer to make dies with.

Robert

[bruce drake]

So you are saying that using a Chamber Reamer on a Die Blank effectively creates a Neck Sizing Die for once fired brass?

I haven't bought the blanks yet because I'm debating on just saving the money to buy the actual dies versus potentially buying several blanks before I successfully create one die...

Bruce

[Mk42gunner]

From the PTG website:

Chamber reamers are furnished in three basic sizes - Finish, resize, and rougher. Finish reamers are precisely ground to cut minimum size chambers and seating dies. Resize reamers are used as precise full length resizing die reamers and can double as precise roughers.

And if this works, here is the link: http://www.pacifictoolandgauge.com/reamers2.htm#solidhss

Basically, what I was saying is that a finish chamber reamer will cut the same size chamber in a die as it does in the barrel, so it will not squeeze the brass down any. It would be just like rechambering a fired case in your rifle.

I really think the best and easiest way would be to just save the money and order a set of dies from CH4D, They list a 6.5-257 Improved 40 degree shoulder for $83.01. I do not know what their quality is like now, but I have a couple of sets of carbide pistol dies from them that are probably thirty years old and they work fine.

Robert

[bruce drake]

that price is about $40 dollars less than RCBS! And well within the operational budget of this project.

Bruce

[Dark Helmet]

Saw your mention of this project in another thread, how goes it?

[bruce drake]

The barrel is now a 6.5 Creedmore. I had a friend trim .25" off the end and cleaned the same depth on the shoulder and I redid the chamber yesterday. This thread can be considered closed as I'm continuing my updates on the new thread.