.309 or .310 in a 30-06?

Y

Yosemite Steve

New member
If and only if my old Savage, which I have had for 30 years, turns out to have a worn barrel, would it be a good or bad idea to shoot a .309 or .310 diameter bullet from it jacketed or not?

It is a Savage 110 and I am not sure how many rounds I have shot through it but it is probably between 1500 and 2500 rounds. It shoots 3 to 4 inch groups at 100 yards with box ammo and averages 1 MOA with custom bullets. I have a couple sub MOA recipes.

Is there a point at which I would benefit from shooting the .309 or the .310 diameters?
 
No, I don't think so. Wear is going to be to the lands, not so much to the grooves. It's the groove diameter that is 0.308. If you wear out the barrel, well first, good for you! You're doing plenty of shooting. Just get a new barrel. It ain't that expensive.
 
Actually, that's only true at the leade into the throat that "engraves" (swages, really) the bullet with the rifling. After that, pressure upsets the bullet outward against the groove floors and land tops, both. Only the inside corners where the lands meet the grooves are sometimes untouched. But, otherwise, there is full contact. This is why lapping and firelapping open both bore and groove diameters. It is also the reason barrel life is traditionally extended by setting a barrel back and re-chambering. The rifling between the throat and the muzzle is fine because gilding metal isn't hard enough to appreciably wear steel. The beat up and heat-damaged throat needs to be replaced, and, in some instances, with higher powder capacity cases, there funneling of the muzzle that requires setting the muzzle back an inch and re-crowning it.


Steve,

.30-06 barrels used in match shooting usually last around 5,000 rounds. If larger amounts of slower powders are used, or if they are driven past the military ammunition pressure ranges, they get only 3,500 or so. The symptom of being shot out is that occasional un-called flyers start showing up. They become increasingly frequent until it is obvious something is amiss.
 
I do get occasional flyers that are usually 2 to 4 inces off unless it is a tuned handload. I have also noticed better grouping after shooting 30 to 40 rounds. High velocities are always tighter groups. I had some undercharged loads with the 180 SST at 2350 fps keyholing.
 
Steve,

No problem shooting .309" bullets, jacketed or not, in your .308" barrel. I shoot Lapua's .309" diameter D46 match bullet all the time in my Winchester SPR Tactical Rifle. .310" or even .311" lead bullets are no problem either, as the lead bullets are relatively soft and will easily conform themselves to the smaller bore size.

Don
 
Yosemite Steve, there so many different barrel today being made. I shoot a Bartlein 30 cal,1/11.25 twist,5r barrel @ 26". what the 5R mean, it's 5 groove barrel and 5R it's from Boots Obermeyer site.

"5R is the form of rifling I developed for use in most target barrels and in many sporting barrels.
These barrels have 5 grooves, and the lands have angular sides. I have observed that bullet jackets
will deform such that they remain closer to the R-form lands than they will to the sharp-edged
lands present in conventional-style rifling. This reduces powder fouling at the corner of the
grooves. The angled form of the lands also helps to reduce jacket failures in quick-twist barrels."

Obermeyer barrel site FAQ
Click to expand...

When poster start talking barrels you should ask who's barrel are they using also spec on barrel.

This is from Lilja site on barrel twist and # of grooves

http://riflebarrels.com/calibers-and-twist-rates/
 
Yosemite Steve said:
I do get occasional flyers that are usually 2 to 4 inces off unless it is a tuned handload.
Click to expand...

If a tuned handload doesn't do it, then it's not a shot-out barrel problem. I've seen bullets bad enough to do that. Especially 147 grain NATO ball pull-down bullets, for some reason, and Winchester's 147 grain FMJ.

What I can't account for, though, it the keyholing you experienced. Assuming you have the usual 10" rifling pitch for .30-06, 2350 fps with that bullet should give you a stability factor of about 1.9, which should be plenty stable. It makes me wonder if there could be a crown issue. Odd.

When my M1A's first barrel died, I was shooting clean slow fire targets pretty regularly. As it began to go, I noticed that one shot out of twenty was a 10:30-11:00 9 that looked through the sights like it should have been a ten. I put it off to me messing up somehow. This was on MR31 reduced 100 yard targets; our rifle league at the time only had 100 yards. It would have been out about 1.25" from center. After a couple or three hundred more rounds down range, it was happening one shot out of ten and I was getting frustrated with myself. Another couple hundred shots after that it was about one out of five. It was at that point it finally dawned on me that I was not the problem. These fliers all happened with the gun's favorite handload, so, in all modesty, I'll asy the ammo source was not the problem.

FYI, usually a 5% reduction is enough for a primer switch.
 
Upon further examination of that target, I think that the paper may have torn. It was stapled to a less than flat surface. There is a lead stain just like the rest of the normal bullet holes at one edge. It was coincidental that the tear looked like side view of the bullet.

I would like to know if there is a way to tell without scoping the bore if the barrel is very worn.

Is this video valid? https://www.youtube.com/watch?v=UsNCqqWgZZA

When I put a bullet in the muzzle it goes in to about 1/8" from the cannelure.
 
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1500-2500 rounds in a 30-06 aren't all that many. That's about the expected life of a .300 wm.

I would think it's something else....perhaps like Nick said a crown issue. If Hand loads don't have fliers, then it's just an ammo issue. My varmint AR 1:8 twist hates 55 gr cheap bulk bullets. I don't know why. It will shoot great with 62 up to 80 gr bullets. But I can't tune a 55 gr bullet to shoot in it, and it ain't for lack of trying. My point? That ammo can lie to you about what's going on.
 
I will say that back in my younger days i do recall shooting it hot enough to sizzle the spit off my finger. I may have done that a couple times.
 
Reading about the crown, i will never ride around with the rifle pointed at and resting on the floor of the truck again.

I think it would be safe to say that the crown is worn. The bevel itself is somewhat uneven, certainly not square to the barrel. The bore itself looks good to me and I have excellent vision. I can see no roughness or irregularities. It is smooth and glossy.

The question I am up against is this: Would it be worth re-crowning? I am assuming that would not be inexpensive. Would it make enough difference in comparison to purchasing a new barrel which would also cost how much? Would a new barrel mean a new stock? I have to say that this rifle was my first and still is my hunting rifle and was given to me by my father when I completed hunter's safety. It has shot close to 30 bucks, 12 elk and a moose. The idea of altering it hurts much less making replacements.

I guess if re-crowning it does not cost too much I might go for that. I just will try not to shoot it more than is necessary for keeping it ready for hunting.
When it comes down to it even 2 MOA will get me a reliable 200 yard shot. I have shot most of my game in the head or the neck to minimize suffering and that is my primary reason for seeking a tiny group.
 
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If the crown looks fine, it probably is.

But... if ALL you're doing is touching up a crown, most gunsmiths can do it for about the cost of a case of decent beer -- and some might actually do it for a case of decent beer.
Find someone with good recommendations from people you trust. Call to get a rough estimate and schedule an appointment (many gunsmiths don't like walk-ins, unless they're in a gun shop).
Then, unless the gunsmith says otherwise, strip the rifle down to a bare barreled action, and take it in like that. Bring the bolt with you (so it can be re-headspaced if the gunsmith decides to pull the barrel -- even though it's unnecessary with a Savage).
 
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