Home Forums Hunting & Shooting Ask The Gunwriters Re-bore question for Mule Deer and other JES customers

What does the barrel diameter need to be to make a 9.3x62?

35 Whelen is as big as i can go.
.575" muzzle

Bugger, at the risk of looking like "that guy" that only posts his best groups on 24HCF, I'll share the story of my JES 9.3x62 rebored Springfield, which was a 1932 receiver (per online records) with a 1934 dated barrel. Plenty of beef in that barrel for the rebore. I got my barreled action back from JES and took it to the range. I had mounted a Leupold 4x Compact (which JB has taught me is actually about a 3.3X) in vintage Buehler mounts, and bedded the action and an inch or so of the barrel shank. I did a rough boresight and shot my very first group out of this rifle with Lapua 285 Mega factory ammo:


Nice! So I went right to my ladder I had loaded up to sneak up on Mule Deer's "250 AB, 60.5 Varget" load. These were the "dirt-cheap" SPS 250 AB seconds that they had a couple years ago. I had loaded three each of 58, 59, and 60 Varget, and four of 60.5. Keep in mind that between each of these groups, I was cranking on the friction dials of the old Leopold compact to get 'er dialed in.
58 Gr.

59 gr and 60 gr

So then I tried "the load"

But note that I am almost 100 FPS below John's velocities, and I reckon my lot of Varget is a little slower in this chambering than John's. So I ended up bumping it up to 62.5 before I got to John's velocity numbers. In the interim, I had done a bit of work with RL-15.5 and had loaded up a batch of 250 AB to the low 2600s for my 2022 elk hunt. They worked:

But after that, SPS loaded up a ton of the 250 E-Tips on their site and I grabbed a bunch, for those situations when a 250 AB "just might not be enough, LOL" I ran them up to the low 2600s with Varget, and they were easily giving me "minute of moose"

but at the end of the test string, I also shot three of my leftover 250 AB/RL-15.5 loads from last year's elk hunt (left target in the pic). The right target is the first of the three 250 E-Tip groups as I was dialing in the 4X compact to the new load.

So how did my JES rebore come out?
Good.

Cheers,
Rex

Sorry Bugger...correct...no action mods. Sorry for getting a little carried away with answering how my rebore "came out."

In what way is your chamber oversized? Headspace? Or a bit big in diameter?

Cheers,
Rex

Just got off the phone with JES. He needs a muzzle diameter of .560 for a 9.3x62.

That's 0.056 smaller than my more robust estimate. I guess what is acceptable must have a bit to do with the power of the cartridge as well. My advice is to go with what Jesse says and not what some random guy on the internet (that would be me ) thought might be the right answer.

Sent a 700 with a pitted barrel in 7-08 to him to have it reamed to 358 and the barrel chopped to 20" and recrowned. 3 groove barrel shoots great. My only issue is its a little rough and like to be shot fouled. Im used to having to clean barrels often. It shoots many different powders into moa. Overall very happy with it. My best group has been a couple of .3's with H4895 and 200 gr Hornady sp.

Yeah, my .358 Win JES 3 groove bore is a bit rough thru the Hawkeye, shows some tool marks. When you recut an older barrel, you take a chance on what the steel is like, not that uncommon to have some flaws and inclusions.

It did foul a good bit at first, but after a DBC treatment and a number of rounds down the spout, it seemed to foul less and less, sorta leveled out.

And, it shoots pretty good as per the target I posted. Of course, a 3 shot group, but it'll shoot almost that good most of the time, just hard to duplicate those trophy 3 shot bragging targets.

But, if you look at Salvage factory barrels thru the Hawkeye, they can be pretty rough, but they tend to shoot a lot better than they look. The acid test is at the range and they pass.

A little fouling doesn't usually hurt accuracy. I don't do an OCD cleaning down to raw steel every time I shoot. Good way to wear out a bore. With DBC, you don't want to do that anyway, just use solvents and a patch, no harsh brushing.

DF