[IDShooter]

Hello all,
     I have recently observed an interesting phenomenon involving my .223 M700 Rem. This rifle was bought new in about 1983 and has been my "working" rifle for years. I used it as a teen and in my twenties to kill many groundhogs. Almost all rounds through the rifle have been 22gr of IMR 4198 with a 55 gr bullet; either a Hornady SX or Winchester bulk bullet. This was the first load I tried and gave such great accuracy that I never messed with it. The bullet was seated to the length listed in the Hornady manual, and always gave -.5" accuracy.
       Now, to bring us up to the present. When I moved to Idaho I left the rifle with my father for the groundhogging chores. A couple of years ago, my folks brought it back out to me on a visit because my dad wasn't going to shoot it any more. Since then I've tried several of the newer bullets and powders, and I haven't been able to get groups much smaller than 1". So I got some 4198 and Hornady bullets: still no better.
     SOOOO, thinking perhaps the throat was a little worn, I tried seating the bullets a little longer to touch the rifling and I can't seat a bullet long enough to reach the rifling!!! Now, when I seat bullets as long as I dare they shoot well again (.4" ) but they don't go in the magazine. I can't believe that the throat has worn that much after approx 2500- 3000 rounds of what I consider a fairly mild cartridge. I don't know how long the throat originally was, but the change is apparent in how differently the rifle shoots.
      Has anyone had a similar experience? Do you think the throat should wear that much?  My best guess is that the throat was long to begin with but has worn just enough to influence accuracy. I don't know?
      Also of interest- the bore is pitted or has some flaws in it that you can see from the muzzle. They have been there since I first got it and took it home and cleaned it. They don't seem to affect it any!
      Sorry for the long post! I'm just amazed!     ID

 

[Contender]

ID,

A good way to tell what the situation is, is to have someone you know who is very narrow-minded stick their head in there to look.

Barring that, a good 'smith with a bore-scope could look in there for you or also you could do a cerrosafe casting of the chamber/throat/start of rifling area.

It is also possible that some damage to the throat area was done with the cleaning rod end banging into the lead area or wearing down the start of the rifling too. This is really easy to do in a 22 bore.

Saying there is pitting in the bore sounds a little ominous.

As a side thought, inspect the muzzle crown area for any damage also that may have occurred. A good nick or gouge to the rifling at the muzzle can really screw the accuracy a bit. I have seen this happen with truck guns before. Also cleaning from the muzzle can do some damage in this area too.

FWIW

Regards,

 

[mcassill]

It is entirely possible that the throat was that long to begin with.  I checked the throat length on my 700VS .308 with the Stoney Point tool after I got the rifle a year or so ago, and discovered that the throat was about the same length as the 168gr Sierra I was checking with! The indicator rod came to within .1" of the end of the case mouth.  Rifle does shoot pretty well though.
One possibility I thought of while reading your post is that you may have copper fouling buildup that the normal cleaning solvent isn't cutting through.  You might try running a patch through soaked with Sweet's or similar nasty cleaner, and see what comes out.
Good Shooting
Mark

 

[MikeG]

well.... clearly it's wearing some, BUT the key question is, does it perform like you need it to?

Under an inch is still not bad grouping.  That's minute-of-groundhog for quite a distance.

I have an old .22-250 that my dad built up on a 1917 Enfield action, when it was still a wildcat.  Can't come close to reaching the rifling with a bullet seated in the case but it still shoots under an inch for 5 shots so that's good enough for me.

If you want to ensure that you've done all you can for accuracy (and to remove any doubt that the pits could be causing problems), I'd shoot 5 or 10 lapping loads through it.  Then give the barrel a heck of a good cleaning and try your loads again.

You might have to work up some new loads for the utmost accuracy.

All in all... under an inch is still not too bad, though it won't win any benchrest matches.  It may be good for that level of accuracy for a few thousand more rounds.

 

[IDShooter]

Hi again,
       Good thoughts from everyone! Some I can rule out though. Contender, I'm not too worried about the "pits" in the barrel. Like I've said, they've been there since I bought it. There are just a few spots approx. 8" from the muzzle. It's not like a barrel that has rusted and is pitted all over. The crown is also good (despite using it alot I've always babied it !). But the cleaning rod idea... I've always cleaned from the breach, but for the first 5 years or so I didn't have a bore guide, so that could certainly be a factor.
       mcassill, I think you may have part of the puzzle there. I suspect the throat was rather long from the get-go. I was 18 or 19 when I got this rifle and I didn't really know about throat lengths, etc. I've been reloading since I was about 15 with my dad's guidance, but we weren't so sophisticated back then! As for cleaning, I assure you I'm very meticulous and use Barnes copper solvent so there is no fouling present! Also, the rifle has so many rounds through it that it cleans very easily.
         And MikeG, I know what you mean. I took the rifle to the range today, and three five shot groups averaged .79 inches with a largest group just over one inch. So it's still not bad. It's fine for coyotes, but marginal for prairie dogs at the in-laws' ranch past 200 yards. Still, I think I'll shoot it for a while before rebarrelling it. ( I have no choice- I spent my money on that revolver!) Then I'll have a barrel with nice tight tolerances put on it!               ID

 

[Marshall Stanton]

ID Shooter,

Perhaps not rebarrelling, but just setting the barrel back a thread or two, then rechambering (and cutting a fresh throat) might be an option if you are looking for quarter-minute of prarie-dog accuracy out of your .223.  It isn't that hard to do, and even a "smith" usually doesn't charge that much for this little task.   I've gotten lots of great shooting out of bores with throats that were totally shot out!  Even bought a few real bargains at gunshows, especially in prarie-dog country, where guns were shot a lot, and the throats gone... unscrew the barrel, set it back a thread or two, rechamber, and presto... a great shooter for a few thousand more rounds!

Just a thought.  It pains me to have folks trash an otherwise good barrel when all it needs is the throat freshened up!

Let us know what transpires!

God Bless,

Marshall

 

[IDShooter]

Marshall,
     I'll have to check to see what my gunsmith charges. I wasn't sure there was enough full diameter shank in front of the receiver ring to do what you describe. I know a Douglas barrel like on my father's rifle has a section over the chamber area that does not taper at all for about 1.5", but the Rem. sort of slopes down from the receiver ring.
      Any way, my gunsmith gets &#3675 for a rechamber job (for example .257 to 25-06) so I'm guessing that it would be a little more to set the barrel back and rechamber.    Thanks!                             ID