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re-barrelling the 30-06, part II

Posted: Thu Jun 13, 2013 8:35 pm
by mtngun
Finally I have been able to get back to the 30-06 project. ;)

Dave Kiff supplied a custom reamer.

The main idea was to get rid of the sloppy SAAMI neck that required 0.314" cast bullets. The reamer turned out perfect except for the throat diameter, which is only 0.304" - 0.305" rather than 0.3085" as I specified. No big deal, as I can re-cut the throat with a throating reamer when I'm ready to do so. In the meantime, the undersize throat may be handy for firelapping. I normally frown on firelapping because it enlarges the throat, but with the undersize throat, who cares if it gets enlarged ?

I had bought a 24" 1-12" Shaw barrel. I went with Shaw because I was on a budget, but later regretted that choice. The bore is rough as a cob and smaller at the chamber end than at the muzzle. So I ordered a nice Shilen to replace it. But then after I got the Shilen, I decided I might as well install the Shaw first, just to get some re-barreling experience under my belt. :lol:

So the Shaw was fitted and chambered. I'll prolly firelap it right off the bat, then re-measure the throat.

More pics will trickle in when the shooting starts. This project will move slowly, but at least it's moving again. :)

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

Posted: Sun Jun 16, 2013 7:18 pm
by mtngun
Today I finished putting the Remington back together and then firelapped the Shaw barrel.

I must have miscalculated slightly because I needed to turn necks just a wee bit to fit the .335" neck with 0.309" bullets. It would prolly be OK with .308" bullets.

I'm not a fan of neck turning, but oh well, it'll work, and I've never had a tight neck chamber before so this will be an interesting learning experience for me. Once the cases are set up correctly, they don't necessarily need to be sized after firing. Just de-cap and reload. Neat.

I fired 12 shots with 280 grit and 24 shots with 500 grit. The load was 9 grains unique behind a 180 grain loverin, at about 950 fps.

After firelapping, the barrel is shinier as viewed from the breech end, however when viewed from the muzzle, you can still see the chatter marks in the grooves. It appears that the button was chattering when they rifled this barrel.

So maybe I should firelap it some more, I'll have to think about that.

So things are progressing slowly, but they are progressing. I'm glad to have the Remington running again, it's a neat gun, very light and well balanced with its kevlar Lone Wolf stock. :)

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

Posted: Sun Jun 23, 2013 2:40 pm
by mtngun
Since the throat on the PTG reamer was smaller than I wanted -- only 0.304" immediately in front of the case mouth -- I decided to use a throating reamer to re-cut the throat the way I had originally intended it to be. There was no budget for a throating reamer so I attempted to make one, and to my surprise, my homemade reamer actually worked !!!

It took 3 tries to get it halfway right, and only halfway. I had intended the pilot to be 0.2997", and it was -- for a while. :lol: But after heat treating and polishing to knock off the scale, the pilot had shrunk to 0.2990."

Likewise I had intended the max throat diameter to be 0.3085" - 0.3090", but it actually ended up 0.3080". :x Nonetheless, I can work around that by either using a 2-diameter bullet or by using a tapered nose die. Plus, I plan to do some more firelapping so the throat may "grow" a little, anyway.

The next step is shoot a few more fire lapping rounds.

Then make a mold or two, and possibly a tapered nose die (I have one but it was made for the SAAMI throat, so I'll prolly make another tapered nose die for this tight 1 degree throat). Then we'll find out what this not-so-great Shaw barrel will do at 2700 fps.

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

Posted: Mon Jun 24, 2013 5:27 pm
by mtngun
A couple of bullets for the new barrel(s). The ogive didn't turn out exactly the way I intended, but it'll suffice for my experiments.

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

Posted: Sun Jul 07, 2013 2:26 pm
by mtngun
I spent a little more time with the Shaw barrel today.

First, I fired 15 more firelapping rounds, bringing the total up to 51 firelapping rounds.   As noted in the bullet recovery thread, the firelapping didn't seem to do much good.   The barrel does appear to be smoother and shiny-er when viewed from the breech end, however I can still plainly see chatter marks at the muzzle end, and it didn't fix the reverse taper.

Maybe if I firelapped 1000 rounds or so :lol: , it would get rid of the chatter and the reverse taper, but I think I've given the firelapping a fair chance.

Next, I attempted to walk up powder charges for my loverider bullets, but I immediately ran into a problem with sticky extraction on nearly every single case.   I tore a couple of rims off the cases before I learned to insert a brass rod through the muzzle and tap the case out.  It only took a little baby tap with the brass rod, but it's not a fun way to shoot :lol: so the problem will have to be fixed before I can get serious about shooting groups.

As best I could tell, the friction was happening at the base of the case, as indicated by rubbing marks on a magic markered case.

My original spec for the reamer was 0.469" at that spot, but in fact the JGS reamer measures around 0.4675" at that spot.   My full length sized cases measure 0.4775" - 0.4778", so no wonder they are a tight fit. :o  I'm not dissing JGS, because I understand they have tolerances for their reamers just like I have tolerances for my molds.   That's real life, and I have to learn to deal with it.

Sooooo...... assuming the base of the case is indeed the sticky spot, it appears that I need more chamber clearance at that spot.   Either I need a fatter reamer to open up the chamber, or else I could prolly make a lap from a fired case and lap the chamber with fine abrasive to open it up 0.001" or so.  It shouldn't take much.

In the meantime, I went ahead and walked up some powder charges.   Compared to a 22" factory barrel, this 23.5" barrel is FAST. :twisted:
I suspect it has more to do with the tight chamber and throat than the extra 1.5".   In any event, I had no problem achieving my 2700 fps goal.  In case you are wondering, the data is "noisy" because I only shot one round per charge.

Things to do next time:
-- lap or re-ream the chamber to fix the sticky extraction problem

-- load to 2700 fps and shoot groups.  Either this Shaw barrel will shoot hi-velocity cast or it won't.  I have a Shilen barrel standing by, so I'm not going to waste a lot of time on the Shaw.   I view the Shaw as a learning experience. :ugeek:

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

Posted: Sun Jul 14, 2013 9:48 pm
by mtngun
Last time I experienced sticky extraction, which I suspected was due to the PTG reamer being 0.4675" diameter rather than the specified 0.469" diameter.

I didn't have time to make a new reamer or money to buy a new reamer, so I had to settle for lapping the chamber. Here's my lap, a reject case with some grooves filed in it to hold the lapping compound. I put the lap in an electric drill and it only took a few minutes to open up the chamber diameter. In fact, I overshot the target and ended up around 0.4695" by the time I finished polishing it. :lol:

Then I loaded up a few of the same full power loads that had stuck before, and now they extract effortlessly, so mission accomplished 8-)

Next step is to shoot groups.

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

Posted: Tue Jul 16, 2013 8:44 pm
by jbquack1
What lapping compound do you use?

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

Posted: Tue Jul 16, 2013 10:26 pm
by mtngun
jbquack1 wrote:What lapping compound do you use?
For the chamber or for firelapping ?

For the chamber, I started with 150 and finished with 500. In hindsight, the 150 was way too coarse so if I did it over again I might start out with something in the 250 - 300 range.

For firelapping, I started with 280 and finished with 500. I believe it is silicon carbide (from memory, I'm not in the shop at the moment).

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

Posted: Wed Jul 17, 2013 3:02 am
by jbquack1
Just seeing what everybody else uses as i have a model 70 action in need of the bolt lugs being lapped.I have 250 grit valve lapping compound, silicon carbide, i also have some finer stuff to finish with. I wouldn't mind messing with hi vel cast, so your threads on this are interesting. I am toying with the idea of a heavy .30 cal for subsonic use, along with a good 180 to 200 grain to run in my 300 wsm for hunting purposes.I'm thinking bore riding tangent for the heavyweight with a long front band,the longest bore ride the program allows with a 75% meplat wich gives a decent looking subsonic nose, a couple decent lube grooves and gas checked. The supersonic stuff i am not sure yet

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

Posted: Sun Jul 21, 2013 8:37 pm
by mtngun
Finally, a little group shooting with the not-so-great Shaw barrel.

I haven't had time to re-cut the loverider mold so these bullets still have the too-small-to-engrave 0.3014" bore riding bands.   The driving bands were sized 0.309", just because that's the smallest die I have at the moment. :lol:   Possibly 0.308" might work better.

The 150 grain loverider was loaded with 50.7 gr. WW760, WLRM primers, and HVR lube.   3.045" COL, to kiss the rifling with the front band.   Average velocity was 2681 fps with 1.2% standard deviation.  I'm used to seeing 0.5% standard deviation in a good rifle load.

The 165 grain loverider was loaded with 52.2 gr. WW760, WLRM primers, HVR lube, and 3.147" rifling to kiss the rifling with the front band.   I did not size the cases.   Most of the necks were tight enough to hold a bullet without re-sizing, but some were a little loose.   More on that later.   Average velocity was 2672 fps with 1.1% standard deviation.   The 1.1% standard deviation seems high to me.

Results of 3-shot groups shown in the chart.   The 150 averaged 5.52" while the 165 averaged 2.44".   Clearly, the Shaw prefers the heavier bullet.   Plus the 150 grainer seemed to lose accuracy and velocity as more shots were fired, suggesting it may have a fouling problem.

Velocities shown in chart.   Way too much variation by my standards, plus the 150 grainer seemed to lose velocity as more shots were fired, suggesting it may have a fouling problem.

Best group of the day, shot with the 165 grain loverider averaging 2691 fps.   If I could do this every time, I'd be a happy caster. :)

Problems Encountered:
-- Too much variation in neck fit.   I've been turning necks on a Forster case trimmer, which is not the greatest neck turner to begin with, plus my only 30 cal turning mandrel is 0.299", way too sloppy for precision work.

-- the M700's trigger is way too heavy for target shooting.   I thought I had adjusted it to about 1 1/2 pounds, but now it feels like about 4 pounds.   Either the adjustment has worked loose or else I'm not remembering things clearly (it's been 7 years since I shot this rifle).

-- as mentioned previously, the 0.3014" bore riding bands don't even touch the rifling.   I suspect the 150 grainer would have shot better if the bore riding bands engraved lightly.

-- my chrono doesn't like the late afternoon light.  I'd like to make a diffuser and/or a cover with artificial lighting so I can chronograph day or night, rain or shine.

Lessons Learned and Things to Do Next Time:
-- get the bugs worked out of my neck turning system.

-- get a cover or diffuser for the chrono

-- recut the 165 grainer bore riding bands to 0.3025" or so.

-- try a 180 grainer and possibly a 190.   Give up on the 150 grain bullet.

-- try to adjust the trigger. If it can't be adjusted, ask Santa Claus for an aftermarket trigger

-- make a 0.308" sizing die

-- make a nose die that matches the throat (cut the tapered part of the die with the throating reamer)