How bad is an off-centre chamber?

[W.R.Buchanan]

Tim: Remington is one of the few major outfits that still makes their own barrels in house. They use WWI and II rifling machines.

I was told this by Mark Gurney of Ruger as Ruger makes the majority of barrels for the rest of the industry. Ruger does hammer forging but the chamber is not part of the rifling procedure. The chamber is reamed after the fact as a 30 cal barrel blank for example could be used for a variety of cartridges.

I have reamed quite a few holes and I am fully aware of ways that a reamer can go out of alignment with a hole, but the shape of a bottle neck style reamer is going to help it go into the hole strait, and is going to require a significant amount of "I don't give a ship," to alter its path very much.

What I could see as a real possibility, is chambering a barrel blank where the bore is off center to the OD and when then running the reamer hard up with no floating capability. The reamer would still "try" to follow the hole but would be forced out of concentricity by the off center hole and as such would flex and bore one side of the hole wider than the other side. Thus would be at its worst at the throat.

OK,,, you talked me into it.

Randy

[swheeler]

tack-driving game-dropping machine built with everything you love about the Model 700, including a hammer-forged barrel,

from Remington ad

[Screwbolts]

By brothers favorite long punch on the farm is the take off 22/250 barrel from his 700. It takes a beating being used as a punch and is holding up very well for that purpose.

Ken

[sackot]

So finally, at long long last, I can report the result of this.

I sent the gun to the UK Remington service centre, as they told me to, so they could look at it.

It took four months and 160 pounds (about $250). They were competent and helpful but very slow, despite repeated calls and emails. This may be because they were also handling all of the UK 700 trigger recalls.

One of the staff read out the internal report to me, and the gunsmith confirmed exactly what I had told them already, ie off centre chamber, machining marks in bore near muzzle and poor crown. They said that Remington give no guarantee on machining tolerances, but do give a guarantee of accuracy, so they took the gun out and shot it, and it met Remington's standards (which will be why I had to pay for it all). I asked just what those standards were, so that I could report it back here. They promised to find out and get back to me, but never did. They also quoted the tester as saying the rifle "was a keeper".

The gun came back with a test card showing a 0.7" three-shot group. I don't put much faith in three shot groups, unless I'm just checking zero after storage, but it made me a bit hopeful.

It arrived back in late October, and the weather here has been so bad I've only just had the first chance to try it out myself. I started with jacketed, 40gr Vmax. Mine are handloads, they had used Norma but the same bullet. Then I tried some cast, NOE 22-055






.
Groups pictured are at 50yd, this is what I happen to have available in the farmer's field behind my house. The first group was with FL-sized, allegedly once-fired brass. The vertical stringing must have some solution, if not for that, it would have been excellent. Next group, two days later now using the fireformed and neck sized brass, still vertical stringing, and actually slightly worse in the horizontal. Finally, 12 shots with cast, pretty appalling.

Cast was with NOE 22-055, wheel weights plus 2% pewter, heat treated. Load was 11gr 2400, a starting load from the Lyman cast manual. I sized to 225, but have now slugged the bore and it's 225, so have sent off for a 226 reamer to make a sizer. I went cheap and ordered from China, so that'll probably be after Christmas.

These results are just preliminary, I've 5 or 6 types of 22 cast to try, and all the possible experiments with alloy and load, before I give up on that. The trigger is still set to lawyer-weight pull, which I must fix but I don't think was the sole reason for stringing. At first blush, it looks as though it might shoot OK with jacketed despite the crooked leade, but the cast is not exactly promising.

[DougGuy]

Wow sad. I would have tried to send the rifle back, or take it back where I bought it, and take home a Ruger.

[detox]

I once purchased a new Remington 700 chambered in 223 and barrel had the same problem as yours. Grouping was about 1" using jacketed. Gun has since been converted to 308 with shillen pre chambered barrel.

Before buying my last Remington 700 chambered in 223 I inspected the chamber, throat, crown, rifling using the Hawkeye bore scope and everything looked good. This gun shoots VERY GOOD.

[Zouave 58]

It sounds to me that this is a bad deal for you. It almost sounds as if a new barrel is in order or perhaps a UK gunsmith can turn the barrel enough to rechamber it with a concentric neck. You haven't mentioned if you can reload for the rifle and I assume you will shoot only factory loads. So long as the bullet does not excessively deform off center in the leade inducing excessive yaw in flight, then you may get lucky. Sorry this has happened to you and good luck with it!

[Blackwater]

On the crown issue, here's something I've done quite a few times with surprisingly great results: I take one of those bullet shaped grinding points for your electric drill, chuck it up, and spin it against my belt grinder to shape it concentricly with the chuck. Then I take small squares of 400, worn 400, 600 and worn 600 grit wet or dry sandpaper, and form then into @ 1" or so squares. I fold them down the center once, then again 90 degreed to the first fold, and this forms a "pocket" when you place the point into it. Then I eyeball line it up on the muzzle, and hit the trigger to spin it about 3 quick rrrr's, reverse and do 3 in the opposite direction. Replace with the worn 400, then the 600, and finally the worn 600, and the bullets will fly out the crown with NO burrs to "grab" them and they'll fly straight - sometimes MUCH straighter than when they came from the factory. This is "rough" redneck engineering, I know, and I had to see a friend do it several times before I had the courage to try it on one of my own guns. I did a 10/22 once, and that alone - no other changes but this - turned it from grouping 1 3/8" at 25 yds. to nice, tight 3/8" (sometimes tighter) groups for 5 shots. That ain't no small thing when hunting small game. All it really does, if you think about it, is simply deburr the crown, and this has, in my experience, been sufficient to produce significant improvement in how many rifles have shot. We just don't get really great crowns from the typical factory sporter these days, and this simple, if seemingly TOO simple, technique has "saved" quite a few rifles from being traded off, and has turned some from sour shooters into very tight shooting rifles a man can be proud of - all with no other changes but the polishing of the crown. Pretty simple to try, and some Oxpho blue will return the color to the crown, too. I know of few techniques that have made as much difference in how rifles shoot, and it's pretty quick, simple and .... it just plain WORKS.

[Blue2]

I have been gunsmithing for a long time and building rifles--I have seen all of the issues mentioned and not just in Remington brand rifles. However to be fair I am often surprised just how well some rifles will shoot with the faults that can be observed in them. They are factory produced hunting rifles after all and not custom assembled firearms with match grade barrels. Most of us here on this forum will have experience playing with older military rifles with dubious barrels and they generally can be made to perform OK for recreation and minute of deer requirements.
I had one new rifle pass through my shop onetime that came from the manufacturer's Custom Shop. In 223 Remington. It would shoot half minute of angle with Hornady factory 50 grain varmint loads but the barrel was a mess inside. I could not imagine how this tube had been chosen for a Custom Shop rifle project. A regular customer would never see this as without a borescope it would not have been obvious.

[Clark]

I am just a putz that has rebarrelled 36 rifles for himself.
But I do have an interesting anecdote.
I bought a Rem700 take off 7mmRM CM barrel of Ebay for very little for amateur gunsmithing practicing.
To put it on a 1908 Braz Mauser I need to cut off the threads and cut the chamber ~ an inch deeper.
I cut off ~ 1" of the breech with a parting tool.
I did not de burr.
When the 7mmRM reamer went in, it started wobbling.
It never straightened out and wobbled all the way until it headspaced.
I put an indicator on it, and the chamber was out +/- 0.005".
I had initially dialed it in with a 0.0001" Intrepid test indicator.
As a joke, I took it to the range anyway with a number of other "good rifles" on 10-3-2009.
I only have 6 shots worth of data, but it was not what I expected at all:
7MM .284 DIA 162GR BIG GAME POLY CARB TIP moly coated
I paid 6.5 cents each as blems.
The powder is 62.8 gr H4350
The OAL is 3.34"
C) The [$33 Ebay] Rem700 take off 23.5" barrel, got the best stock, 1908 Brazilian Mauser action
8 pounds + scope
..1) 0.9" 3 shot group at 50y
..2) 0.75" 3 shot group at 100y

[paul h]

Sometimes it's best not to measure a gun before taking it to the range. I'm glad I don't have a bore scope as I'm sure I wouldn't like what I'd see! That said, I've had four newer production rem 700's, a 221 fireball, a .223 and two .243's. All of them are sub moa with handloads. I also have an older rem 700 .223 varmint rifle that I believe a "gunsmith" set the barrel back and re-chambered and the barrel axis is not parrallel to the action, I'd say if could extend a centerline through the action, and one through the barrel the tip of the barrel would be at least 1/8" off from the action centerline. But it'll put five shots into 1/2" at 100 yds.

That said, a friend had a model 7 that wouldn't shoot, and the barrel is noticeably bent, about 1/2 bullet dia off center.