Fast barrel/Slow barrel

I purchased a Ruger 308 that apparently has a tight barrel (.300" bore) that will allow only minimum starting loads. So far I have tried IMR4895/H4895, IMR4064, and Winchester 748, anything more than the minimum charge and primers are flattened. I am using matched + or - .4grn R-P cases with CCI & Win LR primers, the barrel has a long throat that will allow up to 2.850" as a max loaded cartridge length and still have a .025 jump before engaging the lands. I encountered a similar problem with a 243Win 25-30 years ago that would only allow minimum/starting loads too. I thought stick powder being bulkier than ball powder might be contributing to the problem, I have Winchester 748 on hand that I tried which flattened primers too. I am using Nosler 150 & 165 grn Solid base bullets that have a fairly long bearing surface approx .330" for both bullets. 150 grn Factory Remington and Federal ammunition seem to produce normal velocity (2800 FPS) out of a 22" barrel with normal rounded primer indications!! Both brands of ammunition have approx .250" bearing surface on their 150 grn bullets, could .080 less bearing surface and softer copper jackets produce this sort of anomaly?? William

William:
There are a couple of things you can do that might allow you to shoot through this barrel before either sending it back to Ruger or simply rebarrelling it.
First you can try moly bullets, with Lyman Moly bore cream coated into the barrel.
Next, you can try the David Tubb bore finishing system.
Other than that, Ruger does not have a great reputation on barrel integrity. Call Ruger and if they won't help, buy a good quality barrel and have it installed.
I just rebarrelled a Ruger M77 in 7X57 Mauser. There is nothing on this earth that would allow this barrel to shoot, nothing! The new Krieger SS 1-8.5 twist, 17HV contoured barrel at 30.4 inches was the best thing I did for this rifle. Using the Berger Target VLD 180 gr. bullets, this rifle is now a 600 yard PG killer.

(1) .300 from slugging it?
(2) What does the chronograph say when the primers flatten?
(3) What happens if/when you pull/use bullets from the "normal" commercial Rem/Federal cartridges in your own handloads.
(4) What happens if/when you use the "normal" commercial Rem/Fed powder charges in your own reloads (using same weight Nosler bullets)? (you might want to pull a coupla grains off at trial's start.)

Some barrels just seem to shoot faster, and therefore show pressure signs with lighter loads.

You do not say if you get higher velocities along with your apparent pressure signs, but you should.

Incidentally, in comparing primer flattening, you must be comparing the same primer brand. CCI, for instance, sometimes flattens more than other brands.

The only way you can really know that you are getting higher pressure is to chronograph the loads, and measure case head expansion.

I have a .270 which also shows pressure, but velocity is also high, and most factory ammo shoots about 100 fps faster than it is supposed to.

I agree with the above post about Ruger barrels. They are not known for consistency.

This is the second Ruger I've purchased in the last year,the first rifle has produced very good accuracy with high velocity with both 150 & 165 grn Nosler Solid Base bullet & IMR4064 powder. The rifles Ruger are currently producing have barrels that are being manufactured (hammer forged) by Ruger. To answer MEHavey I used a Scott A. Duff muzzle wear gage to measure land to land diameter which was dead on .300". I've mainly used my chrony on factory produced ammo to establish a baseline and see if I could duplicate or exceed factory velocities. When I ran into pressure problems with flattened primers on starting/min powder charges I felt it was time to back off and approach from another direction. This is probably a good time to remind folks that reloading manuals caution everyone to start with a minimum charge and work up if pressure indicators permit. Mine obviously didn't, I need to find out why!! I do intend to pull some of the factory bullets and use them in my cases, with my powder charge, my primers and the same over all length as the factory loaded rounds and chronygraph them!! I do need to pick up some 150 grn Remington Corlokts & Speer Hot Core bullets and see if they flatten primers with starting loads too. My wife's going on a business trip in a few days, this should keep me busy and out of trouble while she's gone!! Thanks for your responses!! William

If the barrel shoots good, don't screw with it.

The tightest barrels I own are Krieger. I have to cut my 308 and .223 loads at least 2 grains, or I get pierced primers. So, I cut my loads.

Slamfire your comment is dead on, if this barrel is going to limit me to minimum charges then so be it. Often after firing several hundred rounds the irregularities in a barrel smooths and accuracy improves, I'm considering keeping a log of the number of rounds I fire thru this barrel and see if the problem goes away!! William

The confusing thing is that commercial (which is usually as hot as the manufacturer can brag about) shoots w/o any pressure problems, while starting handloads (usually ~10,000psi off max) are flattening primers. That just doesn't logically follow since the commercial should have a REAL problem w/ a tight bore. (I also assume Ruger proof-fired it at the factory w/ commercial as a minimum w/o noticeable problems.)

That's why I suggested interchanging commercial cartridge parts (bullet, then powder, then primer, etc) to see what pops out as the anomoly -- particularly as you're using R-P cases in both instances. It shouldn't take more than 2-3 rounds each to isolate the problem.

Does a different (equal wt/design) bullet, but using the same commercial case/primer powder show a dramatic difference? Then it's the bullet.

Does a starting-mid pressure handload powder (but using the same commercial bullet/case/primer) show a pressure problem? Then it's the powder.

Does a commercial case/bullet/powder, but with your own primer, show a problem? Then it's the primer.

Does a handload using a new R-P case, but the same commercial powder, bullet and primer cause a problem? Then it's the new R-P case.

And finally, what does the chronograph say on the primer-flattening loads vs the commercial loads?

By the way...

1. Have you compared water volume (weight) between the commercial vs new R-P case?

2. Have you weighed the bullets to see if they are mislabeled?

3. Have you measured the new bullet diameters to see if they slipped some 8mm in on you?

4. Have you tried magnum/different primers to cross check primer cup hardness?

I realize that Questions 1-4 above deserve a "...of course I did you dummy..." answer, but I'm just covering the bases and walking down a checklist.

FINALLY, ...have you considered running a Dave Tubbs Final Finish series down the barrel to smooth it out as best it can be? (I had to do this w/ a Colt HBAR barrel two years ago that I couldn't even get a patch down.. It's made a Considerable difference -- even with having had the barrel cut with a broken rifling cutter on one flute.)

http://www.davidtubb.com/finalfinish.html

"....300" bore..." That is the normal bore diameter for any .30 calibre, but not the groove diameter. The groove diameter will be .308".
"...2.850"..." That's too long. Max OAL for the .308 is 2.800".
Flattened primers are one indcation of bad headspace or way overloaded ammo. Bad headspace is highly unlikely. What load are you using?

Sunray since your comment is it couldn't be "headspace" that is exactly what I was dealing with. I trim my cases with a File Trim Die & file the old fashion way, I have been trimming cases this way for more than 40 years, this is the first problem I could trace back to a trim die. Seems the file trim die (RCBS) was setting the shoulder back .003-.004 under minimum step on a L.E. Wilson Cartridge case gage. The Rugers chamber was at the upper end near max so combining the two created nearly .007" headspace between the bolt face and cartridge case. Additionally the rifle does have a .300" bore, I have a Scott A. Duff bore gage and I'm darn sure that's correct. I have no reason to slug the bore to check grove diameter, the grove diameter no doubt is within SAAMI specs. I used powders IMR3031-IMR4895-IMR4064 and H4895, all four powders will exceed Remington's and FC's factory load velocity of 2800FPS + or - 15FPS, all handloaded charges were well under maximum, all velocities were checked with a Chrony chronograph. I am satisfied this barrel is one of the fast ones, I have no desire to load to higher velocities, all the loadings give good accuracy (Remington factory gave poorest accuracy). I have Wilson gages for all other calibers I load for, I attempted to purchase a 308Win Wilson gage but wasn't able to locate one prior to starting to work up my load. I finally found a gage at Precision Reloading Equipment on the West Coast and ordered it in last week. When I finally had my hands on the Cartridge Case gage I gaged a fired case, a loaded round, and a sized but not trimmed case. The problem was quite obvious, I readjusted the trim die to not bottom on the shell holder and that took care of the sizing issue! Hopes this helps someone!! William

With what you describe (and what you're evidently going to have to live with) I strongly recommend Dave Tubbs' Final Finish bore smoothing system -- 10 bullets each with five increasing finer grit surface coatings. If you've used it before, you know what it does -- dramatically decrease fouling (especially jacket fouling) and increase velocity (~60-80fps) at slightly lower pressures. Accuracy/consistency is noticeably improved in "average" commercial barrels, and moderately in "excellent" (e.g. Krieger) barrels.

After using it in three different rifles (HBAR, Garand, Krieger 300WinMag) Tubbs’ system has always performed as advertised (for me). If might give you some extra breathing space.