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Re: re-barrelling the 30-06, part II

Posted: Sun Sep 01, 2013 12:18 pm
by mtngun
I haven't had much time to work on this project, but I did get a couple of new bullets made and also a tapered sizing die that matches the throat.

They were supposed to be 180 grains and 190 grains but they dropped out heavier than expected. This shows the diameters after being sized in the taper die. Most serious benchrest shooters seem to use the tapered bullets fitted to a tapered throat, so I had high hopes that this would be a tackdriver. :mrgreen:

Note that only the bottom 2 or 3 grooves were filled with lube. Normally I'm in the "more lube is better camp," but I wanted to try something different this time.

The bullets were only barely started in the case neck, then allowed to seat themselves the rest of the way when chambered. I'm told that works great if your case tension is just right, but today my case tension was nearly non-existent (I did not re-size the cases, merely decapped them).

In case you are wondering, the camera angle made the bullet bands look slanted. They're not really slanted. :lol:

56 gr. of WW760 ignited by a WLRM primer produced 2688 fps 15 feet from the muzzle. Standard deviation for 16 shots was 0.87%, which I consider a bit much for a rifle load.

Accuracy showed some promise while walking up the powder charge, but then the first 5 shot group was 23 5/8". :x What the heck ? Usually when a load shoots patterns, either the barrel is fouled or else the bullet is getting damaged in the throat. There were no visible streaks of lead in the barrel, but there was a dry grey wash at the muzzle end. The grey wash was the same color as a cast bullet. I'm accustomed to seeing a wet, dark grey/black wash with hi-velocity loads, so I cleaned the barrel and the next group was 3.6" -- nothing to brag about, but at least it was a group, and the improvement after cleaning suggested that the barrel was indeed fouling.

So then I cleaned again, shot another 5 shot group which was 10", and two holes were oval shaped suggesting the bullets were tipping a bit.

Obviously this load had some serious problems so I did not bother shooting any more.

What was different about this load that made it shoot so bad ?
-- less lube was applied

-- I did not size the cases, merely decapped them, so neck tension was non-existent and the "self-seating" feature may not have been working right. The bullets may have been seating too deep and not making firm contact with the rifling.

-- a radically tapered bullet that is more bore rider than loverin.

Things to try next time

-- fix the next tension. I'm told that about 0.001" neck tension is ideal for target shooting. I'm told that it's a good idea to use either a neck sizing die or a collet crimp die. You can get away with not sizing the neck if the neck is turned to a perfect fit, but my neck turning is highly imperfect at the moment. :oops:

-- use more lube. Don't experiment with reduced lube until I have a reliable load.

-- try a deep seated 1-diameter bullet. I know everybody says deep seating is bad but I've usually had decent luck with loverins even when they had to be deep seated.

-- turn the necks for a better fit. I never did get my neck turning problems sorted out so that's part of the reason the neck tension was not right today.

-- anneal gas checks. My unannealed checks spring back to 0.309" when the bullet is sized to 0.3085". For consistent neck tension, the gas check should be the same diameter as the rest of the bullet.

-- I still haven't addressed the not-so-great trigger. It feels like 4 pounds.

There are many other experiments I'd like to do, but for now I need to focus on getting the basics right. This fitted neck business is new to me so it's going to take some practice. It's a good learning experience that will eventually allow me to better serve my customers.

Re: re-barrelling the 30-06, part II

Posted: Sun Sep 01, 2013 8:52 pm
by jbquack1
Following this with interest, i am thinking on a 250 grain 30 cal for subsonic use in my 300 WSM.Fitting the slug seems to be the challenge, i used the online program and came up with a ok design until i read about your streaking issue(less lube),i had made a nose with a long front band with no lube, from what you experienced,i think a .2 to .3 bore riding nose and lots of grooves like your bullet will be better.

Re: re-barrelling the 30-06, part II

Posted: Sun Sep 01, 2013 9:28 pm
by mtngun
Some of the CBA competitors shoot hi-velocity (2500 - 2700 fps) with only one or two lube grooves. But ..... the catch is that they use match grade equipment where everything fits perfectly. My theory is that lube acts like a sealant when the fit is not perfect. The worse the fit, the more & better lube is needed to bandaid the leaks.

Re: re-barrelling the 30-06, part II

Posted: Thu Sep 12, 2013 2:28 pm
by mtngun
Trigger Update: I just checked the Remmy's trigger. Yes, it had already been adjusted, and it broke at 36 - 41 ounces, even though it FELT LIKE 4 - 6 pounds. I tried to adjust it even lighter, but ended up right back where I started, about 2 1/2 pounds, and creepy and gritty, too. :cry:

Sooooo ..... I'll ask Santa to bring me a Jewell trigger. :roll:

Case Neck Update: A Lee collect neck die showed up, and I eventually got it to work, kinda-sorta, despite some serious quality control issues with the die. :lol: I'll do a write up on the Lee die after I finish massaging it. For the time being I have been able to make the Lee die size the necks down to 0.305" - 0.306", close enough.

Re: re-barrelling the 30-06, part II

Posted: Mon Sep 16, 2013 7:30 pm
by mtngun
PROGRESS ON NECKS: using a tight fitting mandrel on my Forster trimmer, and the homemade thickness gage, I was able to turn necks to a pretty uniform 0.012" - 0.013" thick. That was cleaning up necks that had already been turned before. Then I used a .307" M-die to expand the necks for about 0.0015" neck tension with my 0.3085" bullets.

The necks are prolly a little thinner than ideal, since the ID is 0.309" - 0.310" after firing. There's prolly 0.001" neck clearance with a o.3085" bullet. But they're uniform, and 0.001" clearance is much better than a sloppy factory chamber. So that problem is more or less solved. 8-)


Today I re-tested the 190 grain tapered spitzer, this time sized in a tapered die for a "glove fit" in the throat. About half the bullet was tapered, the other half 0.3085" and lubed. Seated out to engrave just lightly.

55.5 gr. 760, 3.253" COL (barely engrave) -- 13.5 MOA, 2789 fps, too hot, so I dropped the powder charge and seated deeper.

55.0 gr. 760, 3.233 COL -- 12.5 MOA, 2766 fps, too hot, so I dropped the powder charge and seated deeper.

54.5 gr. 760, 3.213 COL == 16.5 MOA , 2694 fps, still a little warm.

Velocities and pressures were higher than last time even though I used less powder. Apparently the "glove fit" boosts the initial engraving pressure considerably ? :shock:

SO WHAT THE HELL IS WRONG ? A few weeks ago this barrel was shooting 2" groups with hastily assembled loads. Now after going to great lengths to get the neck fit and bullet fit just right, it barely stays on paper. Something is seriously wrong.

I don't know what is wrong so some detective work will be required. Usually when accuracy is that terrible, it's either a bad scope or a bad throat.

Re: re-barrelling the 30-06, part II

Posted: Mon Sep 16, 2013 8:18 pm
by mtngun
Forgot to mention that today's 190 gr. loads were tipping just a bit on the paper. Not every shot, but about 1 out of 3.

It's also worth noting that when the barrel shot those 2" groups, it was with a 170 grain bullet (from memory), not a 190 grain bullet. It's possible that the 190 is not stabilizing in the 1-12" twist.

Re: re-barrelling the 30-06, part II

Posted: Sun Oct 06, 2013 12:27 pm
by mtngun
It's been a while since I have been able to do any shooting or gunsmithing, but I did make a 170 gr. spitzer. This was to test whether the bad accuracy with the 190 grainer was due to instability. We're confident that a 1-12 barrel will stabilize a 170 (and usually a 190, too).

Also, a Jewell trigger showed up to replace the creepy 2 1/2 pound factory trigger. The Jewell came set at 9 ounces and I left it like that. It's awesome. 8-)

The 170 grainer was nose-sized in a 1.2 degree tapered die, then the rest of the bullet was sized 0.309". When sized this way, the 0.307" band tends to engrave hardest, with the other nose bands barely engraving at all, so the nose taper is not optimal for this barrel's throat. :( I think in the future I will attempt to make my nose dies taper about 0.1 degree less than the throat, to ensure that the 0.302" band engraves first and hardest.

Load was 54.5 gr. WW760, WLRM primer, 3.246" COL, which engraved fairly hard.

1st 5 shot group -- 8.3" (4 in 2.2")

2nd 5 shot group -- 27.5" wild, all over the target

Then I cleaned the barrel.

3rd 5 shot group -- 8.9"

All bullet holes in the paper were round, there was no evidence of tipping.

Velocity averaged 2751 fps, with 0.7% standard deviation. The load was a little warm and in hindsight I should have dropped the powder charge to produce my desired 2700 fps.


-- fouling does seem to be a problem at 2700+ fps.

-- we're confident the 170 grainer is stablized, yet accuracy still sucks

-- the 1.2 degree tapered nose is not optimal for this throat, though I doubt that is the "main" cause of the wild shooting.

-- I suspect the main problem is either fouling or else a throat that is not centered in the barrel


-- make a throat impression to determine whether the throat is well centered

If the throat is bad, I can make a new reamer with a snug pilot that will clean up the throat.

If the throat looks OK, then I'll have to conclude that this barrel is fouling too much to shoot high velocity cast. Remember, it is rough as a cob and tapers from 0.307" at the breech end to 0.308" at the muzzle -- all wrong for cast bullets.

Re: re-barrelling the 30-06, part II

Posted: Sun Oct 06, 2013 7:44 pm
by jbquack1
Thinking that the reverse taper is giving you problems.Wonder if 100 shots with lapping compound might straighten things out?i have fire lapped my pistol barrels and it usually takes a 100 to 200 shots to clean up any issues i find.i clean after every 5 shots in my revolvers when lapping, you have said you may rebarrel so not sure it's worth the effort.

Re: re-barrelling the 30-06, part II

Posted: Sun Oct 06, 2013 8:58 pm
by mtngun
jbquack1 wrote:Wonder if 100 shots with lapping compound might straighten things out?

It has been firelapped, as posted previously. Don't remember how many shots total, but seems like 50 - 100. Maybe if I firelapped 2000 shots it would get better but I'm not that motivated. :lol:

I can't rule out an eccentric throat since the pilot of the throating reamer was 0.003" undersize. So a throat impression is called for.

Odd thing is that the barrel showed some promise early on and then went to hell. It's possible that it has fouled and I'm not getting it clean enough when I clean it, though all I am finding is grey wash, no flakes of lead. The grey wash cleans out easily.

Yes, a better barrel is in the works. The main thing with this Shaw barrel is to figure out what I'm doing and get all my newbie gunsmithing mistakes sorted out so that I do a 1st class job on the next barrel.

I've already learned quite a bit from this barrel even though it shoots like crap. I've gotten comfortable with neck turning and I have a better idea of what I want for chamber and throat dimensions. I'm getting close to having the tapered sizing dies sorted out. Eventually things should start to click, or so I keep telling myself. :lol: