New Rifle Difficulties...

T

Tom68

New member
Hi friends, this is an extension of an earlier thread that I started just after I bought a new Savage Model 10 heavy barrel in .308 Win. In my earlier thread I pushed through a myriad of potential issues, and learned a lot in the dialogue. for those who may wish to revisit the discussion, it can be found here (hope the link works).

http://thefiringline.com/forums/showthread.php?t=567740

Today I gave up. I have determined that a short throat is the root cause, and have sent the rifle back to Savage to have the chamber examined, and re-cut if necessary. I have noted a few factory rounds showing pressure signs, and today when my handloads with a different bullet (Hornady Match 168s, everything before had been 168gr SMK) measuring 2.763" OAL (SAMMI max is 2.810") wouldn't even chamber, I knew I had a problem...and there were marks on the extracted bullet. I've had to stop with several test loads after the first firing because the bolt locked up... and this was at -5% of max load. I have yet to test a powder that could produce even -3% of book max without showing excessive pressure. So, I'm pretty certain by now that the rifle was shipped with a very short throat.

Now, I know that every rifle can't safely shoot book max with every powder listed in every manual... but when you can't reach max with ANY of them, from any reference... and you can't even get within 3% of max without causing problems, then there must be an issue. My only hope is that Savage receives the rifle and chooses to examine it critically to determine the problem. This is the first time I've sent a firearm back to the factory for what I consider to be a factory problem, so we will see.

in the meantime, deer season is upon us soon, so not having the target rifle shouldn't be a major problem, as I expect to have plenty to do in my spare time until late January.
 
Tom,

I think you are operating on an erroneous assumption. SAAMI max is a general not-to-exceed number for ensuring fit in a magazine. It has nothing to do with what you can expect a chamber to accept. That depends entirely on bullet shape.

For example, you would not expect a .308" diameter full wadcutter to be able to seat out to 2.810" and still chamber. That wide nose would find the throat first because only a long nose that is narrower than the bore for a good distance along its ogive would slip in past the throat without being wide enough to interfere with it.

In comparison to the 168 grain MatchKing, the Hornady 168 grain bullet has a shorter secant ogive nose and a longer bearing surface, so I would not expect you to be able to seat it out as far as the SMK. So the question is, did you check with Hornady for the maximum COL they use with that bullet? If it is less than the COL you used, you have your answer. If it is more, then you are right that you have a short throat, or else a freebore cut with a worn reamer that didn't cut it wide enough (not unheard of).
 
Unclenick, I do not have access to Hornady load data, so I was unable to reference their OAL for their 168 grain match bullet. However, I understand completely your advice regarding differences in secant ogive nose profiles. Even using the eyeball method, I was able to discern differences in the two bullets side by side; however, I incorrectly reasoned that a -0.157" from SAMMI AOL should be sufficient for starting loads to at least 3% book max.

I use Redding seating dies, which contact the bullet on a consistent diameter ogive as opposed to the bullet tip (I figured this out long ago, when using the same die to seat Berger bullets... and Redding sent me a #20 stem expressively for Burgers). So, I do recognize the differences in bullet types and how they seat based on the die being utilized...... but we're talking about nearly a 2/10" difference from SAMMI max, on a VERY commonly used bullet type. I've come to the conclusion that the throat must have been cut short.

Any other potential issues which I may have missed?
 
If you email Hornady, they will send you information on it without your having to buy the whole manual. Also, you can call them.

What maximum COL could you use with the SMK? In the Sierra manuals it will load to 2.800" in the .308, which is the military maximum for 7.62 NATO (don't know why SAAMI put an extra 0.010" onto it). But for .30-06, for which the maximum is 3.340", the only suggest loading it to 3.290. This is because the nose is shorter and wider than the military FMJ's the cartridge was designed around, and the the .30-06 chamber lacks a freebore. Just food for thought.
 
308 data

From the hornady 9th edition: col 2.800 for 168 bthp # 30501, same col for 168 a max # 30502

From Sierra 7th ed. 168 match king #2200 coal 2.800
 
It is not fair, most have a picture of a rifle, they hold it up and it looks just like their rifle. For me? That is where the similarities end.

I have factors, factors can not be seen. And then I am the fan of the running start, I want my bullets to have 'the running start'. I am also the can of cutting down on all that case travel. reducing case travel can increase pressure, the jump start can decrease pressure. Then there is the inside diameter of the barrel, a small diameter barrel can increase pressure, increasing the diameter of the barrel can decrease pressure.

If I am concerned about the onset of pressure I measure the diameter of the case head. I am not talking about the pressure that renders my guns scrap I am talking about the pressure upsetting my case heads.

F. Guffey
 
Yes, sending it back is a decent idea. Sounds like the OP knows what he's doing with his reloading, so it appears that something is wrong with the rifle. At the very worst, Savage will tell him if the chamber is properly done, or not. I had a similar problem with a new barrel and finally had the chamber recut. Problem solved.
 
Sounds like the OP knows what he's doing with his reloading,
Click to expand...

I know reloaders/smiths that sent rifles back to Savage and Marlin. They did not like the answers they got. Both manufacturers sounded like reloaders on a reloading forum, they claimed they had tolerances and they had +luses and -inuses.

F. Guffey
 
yes, quite frankly I will be interested to see the sort of response I get from Savage. For one, I am not aware of their opinion of handloading--I need to re-check the operator's manual to see if they, like some other manufacturers, claim that shooting "remanufactured" ammunition will void their warranty.

I certainly do not claim to be all-knowing all things reloading--and I'm aware of many of my limitations--but I have been doing this for over 5 years now and have loaded many thousands of rounds on my single-stage press, most of which have been bottleneck rifle cartridges trying to improve accuracy in hunting rifles. (from a different thread, I tend towards being a handloader vs. a reloader).

That being said, I've found the pressure limits of several of my rifles and immediately backed away... but this particular rifle is behaving in a way that is completely different than any I have experienced before. It seems highly unlikely to get excessive pressure so near a starting load, and with a COL so well under SAMMI max. So we will see.
 
I hope your rifle does not come back like many remingtons, with a huge freebore dimension - where you can't contact the lands if you wanted too.

If I was still trying to be a precision shooter, I would be happy with the lands overly close to the chamber.
 
You must log in or register to reply here.
Back
Top