New project: Ugly Duckling

[Fast14riot]

This R700 has been sitting on the consignment rack at my LGS for a little over 6 years now! Originally had a price tag of just under $900, but being god awful ugly, barrel is 6x250 and this particular gun store is more of a glock and tacticool shotgun place, it just sat there. I sure wasn't willing to pay that much for little more than an action.

Fast forward to March of this year and I stop by, see they dropped the price to $495! Now we're talking! I put it on layaway, not wanting to raise any red flags with my accountant (I eventually told her before I paid it off, lol) and just threw a little extra lunch money at it every chance I had. Today was pick up day!

The gun: R700 SA XTC rifle, unknown 6x250 barrel though it came from a guy who was pretty particular, so I assume its cut rifled. Bolt has Sako extractor installed, jewel trigger, old HS Precision bottom metal and magazine, stock appears to be a bastardized McMillan prone stock.

The plan: I picked up a lightly used (412 rds) Bartlein 30" Med Palma 260AI barrel last week chambered for a Barnard S for a really good price, which is same thread as Rem and my smith and good buddy agreed to recut the shoulder and tenon to fit the R700 for me. I'm going to fix the ugly on this stock and probably sell it with the bottom metal. I have an old single shot rimfire 40xb stock it'll drop right into. Take the money from the stock and roll that into a decent scope. Also going to send the bolt off to Carlsbad.

Posting here so as I get to it I'll update.

 

[littlebuddybr]

Sounds like a fun project.

 

[Fast14riot]

Got the barrel quickly cleaned and scoped, it doesn't look bad at all. Good enough that I found some dies and brass to give it a shot.

Barrel is 1:8 twist. Ill soak and scrub it really well before I shoot it.

If it doesn't shoot, I'll screw on the 260AI barrel.

 

[PigButtons]

Nice of you to give that ugly duckling a good home. Please keep us updated.

 

[Fast14riot]

Well, since I'm waiting on brass and dies to come in the mail, I thought I would do some educated estimation in GRT. Once I get some brass formed and am happy with how it chambers, I'll redo my measurements, but so far this data seems to align with other info I have found on the net.

I set Pmax to 58,000psi to keep working pressures safe and reasonable. But looks like around 34gr H4350 with a 107smk would be close to max and produce roughly 2800fps.

 

[joshb]

Nice snag! That’s one of those “the parts are worth more than the gun” guns!

 

[ar15Jeff]

I still have a XTC 6-250 that I built in the 80's, before the other popular 6mm's came out. Great little round that has been lately surpassed by more modern cartridges. Hodgdon had reloading info on their page before the removed it, but I found out it was a little hot in my rifle. My first indication of high pressure was primer pockets getting loose. My best load was 32.5 of N150 with a 105 Amax bullet and a silver Winchester primer. I could get more velocity with 4530, but the accuracy wasn't as good. YMMV, always work up your loads. Would easily clean a 600yd target. Also, fed out of the magazine like a greased sausage. Average velocity out of my 26in barrel was around 2880fps with an ES of 14 and SD 5.5.

 

[Fast14riot]

Nice snag! That’s one of those “the parts are worth more than the gun” guns!

Exactly why I bought it. I went into it without the barrel being usable, but it looks good, and for the price I paid i couldn't get an action, let alone a jewel trigger and stock.

 

[Fast14riot]

I still have a XTC 6-250 that I built in the 80's, before the other popular 6mm's came out. Great little round that has been lately surpassed by more modern cartridges. Hodgdon had reloading info on their page before the removed it, but I found out it was a little hot in my rifle. My first indication of high pressure was primer pockets getting loose. My best load was 32.5 of N150 with a 105 Amax bullet and a silver Winchester primer. I could get more velocity with 4530, but the accuracy wasn't as good. YMMV, always work up your loads. Would easily clean a 600yd target. Also, fed out of the magazine like a greased sausage. Average velocity out of my 26in barrel was around 2880fps with an ES of 14 and SD 5.5.

I just got my sizing die and brass yesterday. Haven't had a chance to play around with it yet, but plan to this weekend. I haven't even measured the barrel length yet, lol! The current stock is set up with a Gen 1 HS precision DBM, but I'm most likely going to make it single shot.

 

[Fast14riot]

Well, the joys of buying old wildcat dies on eBay! I had some RP 22-250 brass, freshly annealed, ran it into the die, seemed rather difficult and completely crushed a couple cases. Since I didn't measure the expander button when I took the die apart to clean it, I did after that. Hmm, .276" sure doesn't sound right?!

So, I decided to short stroke a case or two to get the necks opened up, then pull the decapping rod and size it back down that way, it measures between .256" and .260" OD. A bit small for 6mm, looks like I'm going to need a 6mm tapered expander button from RCBS. Thankfully they're cheap.






I'll get back to playing with the gun this weekend. I'm frustrated with this for now, so time to put it all away for the night. Will post any updates as I putter along on this build.

 

[Fast14riot]

Little update, some more frustration and a victory!

Dealing with this vintage RCBS franken-die has been a lesson for me. I ordered up a new 6mm tapered decapping stem/button and RCBS sent me a lock nut for free since it was missing (Kudos to them!). The lock nut arrived and it 10-32 Hmm... the stem that came with the die is 1/4-28. Which means the guide bushing (learned the name for that part from RCBS, lol) is too big for the 10-32 stem I have on the way. [Let's see who catches my oversight in mathematics here].

So, I screw the new 6mm tapered expander on the old stem, so it fits the existing guide bushing. Run a case up and it comes out looking like it had a swim in a cold lake. Collapsed another one. Damn. Fuggetaboutit for the night. Well, had to swing by my dads for something and get to talking, I ask if he has any spare 6mm RCBS die parts sitting around (this is only my second RCBS die, I just dont use them) and sure enough, he has an extra standard expander button and a 10-32 guide bushing! Stem that came with the die on the left.



Screwed it in, grabbed a piece of brass and it goes through like butter! Pull it out and sure enough, a properly sized 6mm-250 case! Finally! Then, my oversight became clear. 1/4-28 decapping stem measures 0.250" diameter, thats bigger than 0.243, lol! I look at the old stem and yep, brass smeared all over it!



Now the brass chambers, although quite snug around the base, it chambers. So I grabbed an extra 6br micrometer seating die, backed it out a little and seated a couple different bullets to get an idea of what kind of lengths I'll be working with. A speer 80gr Spitzer FB and a Hornady 108 eldm. Both seated with the base right above the donut area. 108 was 2.746 COAL and 80 was 2.450.

L-R, 108eldm, 80sp, 6br 107smk



Next up is measuring distance to the lands and figuring out my starting load then dealing with what I feel is excessive pin fall of 0.306 and very heavy cock on close. Should get to dive in to that this weekend.

 

[JSH]

Hornady expanders work well to bump up a neck.
The RCBS expander, I would chuck it up in a drill motor and do a polish job on it.