What's up with Remington and 1/10 twist?

Bart B. "off center gasses" might not be the shooting term, but basic gas chemistry and physics tells us that in an enclosed environment pressure is equal against all surfaces. If a crown is out of true, once the bullet (the only thing keeping the gas in) passes by the out of true portion and unseals the system that is where the gas will preferencially go instead of "pushing" against the bullet. Too much gas pressure on one side of the base of the bullet on exit from the muzzle is not good for accuracy, and boat tail bullets have a longer bearing surface for the gas to interact with over flat base bullets, which as you noted have an accuracy advantage at short range.

A lot of milsurp rifles have that "counterbored" muzzle because careless soldiers with steel cleaning rods made the muzzle not a true circle and accuracy suffered.

I'd still try a recrowning job, recess the muzzle 1/8 of an inch and machine an 11 degree target crown.

Jimro
 
Looks like a lost cause. 1/2" diamonds. One target shot with 175 SMK over 44.2 Varget. Other target 165 gr. Hornady InterLock SPBT over 45.0 Varget. 4 different bullets and 2 different powders yielded pretty much the same results in prier workups.

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Have your gunsmith take the barrel off and see if your rifle is one of those M700's in which the receiver threads were so poorly machined, that Remington poured glue around the barrel shank to keep it in place.
 
Slamfire, thanks for the heads-up. First I've heard of that one. :( I'll find out when he installs the new barrel. Haven't ordered it yet so I don't know how long it'll be before I get it. Smith will be squaring up the action and cutting new threads so if it is a Remington patch-job it won't matter in the end.

I just finished taking the scope off and found a loose rail screw. Wasn't loose last time I checked it... trip before last. When I say loose it just took much less torque to brake it lose than the other three. Two front screws were tight tight. Forward rear took a little pressure to break loose (less than the front two.) but the one all the way in the back turned with very little pressure. Had maybe 5 in. # of torque on it. Threaded holes and screws were cleaned with mineral-spirits then Acetone then RED LockTited so I don't understand why the rear screw turned so easily. I pulled the action and found that the recoil lug isn't square in the action. Only the lower edge is making contact with the beading-block. That will also be taken care of when the new barrel is installed. Bedding block seems to be square. When cleaning I did notice a tight/rough spot in the bore about a third of the way forward of the breach. Felt like it cleaned up so it may have just been carbon/copper fouling. I had put about 125 rounds through it since the last cleaning. Barrel cleans/cleaned up pretty easily. Couldn't find anything else out of whack.
 
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Jimro, I agree that gas will escape first where the bullet's heel first clears the crown. That's easy to understand. But if it's minimized, it won't effect accuracy to any observable amount. Here's why.

I've worn out 4 barrels in 7.62 NATO chambered Garands and cleaned them every 30 to 60 shots with a solid steel rod that rubbed away the barrel steel back from the crown. The bore and groove diameters were worn away evidenced by the lack of copper fouling where the wear was. Copper fouling stopped about 1/8th inch back from the muzzle for every 1000 rounds. After a total cleaning removing all the copper wash, it would start building up again but never where the bore and groove diameters has been enlarged by the cleaning rod lapping away metal. And there was always more in one area (typically at 4 o'clock in the bore) from how I used the cleaning rod and it was twice as far back on one side opposite the other. When the barrels were replaced at about 5000 rounds, there was no copper wash for about 3/4ths inch back from the muzzle on one side and about half that much on the other.

This tells me the metal wore away more at one point that the place opposite it in the bore. As more metal wore away, more gas escaped at that point at the bullet's heel than the others. So there was some uneven gas ejecta around the base of all bullets fired starting with the first hundred or two fired.

Yet accuracy stayed the same from brand new to worn out barrels. With good commercial match ammo, 2/3 MOA at 600 yards was normal for about 3000 rounds. It opened up a tiny bit after that but still stayed under 1 MOA for another 2000 rounds. No discernable change in zeros for any range was observed.

Why? The only answer I can come up with is the gas ejecta at one place around the muzzle was very repeatable from shot to shot. As accuracy with rifles is typcally best defined as reducing all the variables to zero (or as close to zero as possible), the varable in this gas ejecta issue with bad crown is not a problem when it's not very much. But a horribly mutilated crown may well cause other issues as that will tip the bullets way too much upon their esxit from the muzzle. I've seen some crowns with a protruding burr that had to groove bullets as they exited.

For all the others, a "crown" is typically referred to as that few thousandths of an inch where the muzzle's angled away from the bore diameter out just past the groove diameter. The "face" is the muzzle shape from the crown's outside to the muzzle's outside diameter. The face can be flat, rounded or angled to some amount as counterbored back from the muzzle.
 
Jerry,

Too bad that 'smith didn't measure the barrel's bore and groove diameters; bore scopes don't do that.
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Agreed! 900 ROUNDS?? :eek: And no sign of MOA?

That barrel should have been pin guaged about 825 rounds ago!
 
Went back to the range yesterday after a complete disassembling and reassembly. Took 175 SMKs and Hornady 165 SPBT. No good!

I'm waiting on replies from one barrel maker and one suppliers.

Anyway. In my search for information I found this video. I won't be installing one but I thought it was an interesting device. http://youtu.be/DhRIebOY4Jk
 
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I may have missed it but have you shot any factory match ammo out of it ? Federal GMM seems to be the cats meow when it comes to shooting well in any rifle .

I'm just now getting in to this whole reloading thing so I'm a bit lacking in the knowledge area . FWIW I have a Savage with a VERY short throat and while researching that issue I fond a few articles stating the the Rem 700 at times has a HUGE/LONG throat . Some were saying they could seat a 175gr smk to a OAL of 2.930 and it still be off the lands . Not sure what you were seating your bullets at but maybe you have one of those long throats and the jump is hurting your accuracy .

In contrast I have to seat a 175gr smk to a OAL of 2.730 to stay off the lands of my Savage . I was at the range last Friday trying out some hand loads and the guy next to me saw my notes and commented on the OAL of the 175gr smk . I told him the issue and he said thats not right and gave me some 308 military match ammo to try . I could not even get that stuff to chamber in my rifle . Could not get the bolt to close and did not want to force it .

So my short throat issue makes me think maybe your jumping your bullets to far and there going down the barrel back wards :eek::D . OK maybe not that but I here some rifles don't like to be jumped .

Like I said I'm pretty new at this so what I just said may not mean a thing but I thought I'd throw it out there .
 
I haven't shot factory ammo in a rifle other than 17 HMR and 22 LR in 35 years. Yes, my Remington throats are so long that a 180 set to .005 off the lands won't stay in the case. I believe they have to be something like .150 off the lands to be fully seated in the case neck. They make quite a jump but that's Remington for you. I've loading the SPS from magazine length 2.815 down to 2.800.

I have a 700 BDL in 30-06 1/10 twist that hase the same L O N G jump. Only likes 150 gr. bullets. It will shoot 1/2 MOA or less with Hornady 150 gr. FMJ and 1/2 MOA with Hornady 150 SPBT. Anything else it shoots MOA or lager. I bought the SPS for fast handling and shooting heavy bullets. It won't shoot heavy bullets and since the 06 shoots 150 gr. I don't need a 308 that only shoots (if it would even shoot) 150 gr. or lighter bullets. After the smith is finishes it won't be as fast handling but will shoot anything from 125 gr. to 180 gr. bullets to 1/4 MOA. That's what the bench-rest rifle he built for me does with me on the trigger and I'm sure the SPS will do the same when he's finished. But it won't be an SPS anymore. It will be a completely custom rifle.

Took me under 100 rounds to work up the loads for the custom gun he built. 1030 rounds and still haven't found anything the SPS will shoot under 2 MOA.

Sounds like your savage has a really short throat. If I remember correctly normal 308 length should be 2.800. Lyman calls for 2.810. My custom rifle is reamed so 2.810 puts the bullet at the lands. I load so the ogive is .005 off the lands. My CZ in .223 likes 53 gr. SMKs .030 of the lands and 65 gr. SGKs .002 off off the lands. It's nice when a chamber is reamed to the proper length. Remingtons cambering leaves a lot to be desired. But I supose if one wants to shoot 220 gr. bullets it's probably right up their ally. :rolleyes:
 
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Updated with dates military shooters had "Sierra" and "Lake City" rifles.

Metal god, Federal Gold Medal Match ammo won't shoot too good in barrels with oversize groove diameters. I tried two different lots of it in two different Win. 70 .308 Win. factory match rifle barrels. Neither shot the Federal ammo as accurate as it did two lots of M118 7.62 NATO match ammo. With both barrels' groove diameters in the .3085" and .3086" range, only those .3086" diameter M2 172-gr. FMJBT arsenal match bullets shot well.

This is the reason why many military team members in the '70's and '80's shooting 7.62 NATO chambered semiauto rifles had one called their "Sierra" rifle and the other a "Lake City" rifle. The Sierra one had smaller groove diameters and shot Sierra's HPMK bullets more accurate but also shot the 172's very well. The LC rifle only shot the LC M118 ammo accurate.

In barrels with smaller groove dimensions, the Federal ammo does indeed shoot well. As does duplicating its component suite making ones own handloads.
 
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I had to back track some, to see your rifle to understand why you're so disappointed. I saw the targets and thought that, while they are nothing to brag about, but adequate for medium range deer hunting. Then I saw that you have the tactical version.

My first magnum centerfire rifle was a MDL 700. This was 1976. The best I was ever get was 1.5", five shot groups, with my reloads. My buddy who found an Arisaka 99 in his attic, that his father had brought home after WW2. He invested $35 in dies and bought 40 pieces Norma brass, some weird 173gr bullets and proceeded to shoot rings around my new sexy magnum rifle. He regularly was able to 5 shot groups well under an inch.

My, uncle a Methodist minister and a gunsmith, had no love for the Rem 700. He had MDL 721's, MDL 70's, Weatherby's and informed me that drilled bar stock as a receiver, washered recoil lugs, and fused bolts were a crime and a sin! I thought my 7 mag was all there was. He left me his MKV Deluxe, and not too long after that I sold my Remingtons. I now only own Weatherby's, Coopers, Rugers and a Belgian Browning.

My point is a rifle built in the old ways, with modern materials, will seldom disappoint. They will put a hurt on your wallet though. A rebarrel may help, but, shouldn't be necessary, IMO.

You can certainly make a REM 700 accurate if are willing to invest some more money, but, you know what I'm getting at. I feel your pain!
 
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Sierra280, yes, the M118LR ammo's loaded with a Sierra 175. The original M118 ammo introduced in 1964 had the military 172-gr. FMJBT M2 .3086" diameter bullet; the same bullet used in machine guns starting in the 1920's and a few years later in .30-06 arsenal match ammo until 1967. Between these two was the M852 ammo that came out around 1980; it had Sierra's 168-gr. HPMK bullet.

I edited my earlier post on "Sierra" and "Lake City" rifles used by military team members to reflect this. Thanks for your comments that got me to thinking somewhat more precise about the history of such stuff.
 
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Hesdliner, what hurts the most is my 1973 vintage 06 shots MOA or slightly larger with factory Remington 165s and most of my hand losds. Took a while to find out it likes 150 gr. bullets enough to shoot 1/2 MOA and smaler. The SPS, a praised sooter by many, won't come close to the OLD 06. Yah, its taking some $$$ but it will be a tack driver in the end. :D
 
i bought a rem 722 in 308 made in 1955 at a very good price in ex condition that was full lenth glass bedded, it had weaver bases on it and i mounted a 12x leupold on it to see how it would shoot. the only shells i had were 175 smk,s with 43grs varget that i shoot in my match rifle,well it shot them into 3/4" groups, but they were four inches left of center with the adjustment turned to the wall. i remover the scope and weaver bases and found that the front mounting screw holes in the reciever were off center(maybe why it was a good price). i mounted a redfield base with the windage adjustments on the rear and now have a ex glass bedded rem 722 in 308. eastbank.
 
It is possible you could have a warped barrel. I have a 700 ADL Varmint that I bought a few years ago at Dick's. It shot pretty decent. I decided I anted to cut the barrel down to 20". When I went to pick it up the gunsmith told me the barrel was warped and wobbled in the lathe. Luckily the warping started at around the 21" mark. It is now straight and wobble free. Two days ago at the range the best group I had was .307" at 200 yards. This is with the factory injection molded stock that has the buttons at the end that contact the barrel. I have read that in some rifles there is a reason for the buttons making contact with the barrel.

I know this is a 1:12 barrel, but just offering up another possibility.
 
Jerry45 said:
Remington 308s are 1/12.
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People keep telling me that, and that might be a general rule of thumb, but I have a Remington 700 ADL in .308 that left Ilion in 1983. It's got a 1:10 barrel with the Remington date code on it. Remington may have installed different twists at different times for whatever reason they might have had for doing so.
 
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