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Posted: 1/23/2009 6:40:42 PM EDT
Bought a savage model 10 heavy barrel, began reloading the .308   I have been loading for years in the 7mm mag and 30.06 without any problems.  After some research I chose Varget.  My load go as follows

Winchester brass
Win LR primer
Hornady 168 grain BTHP match with moly coating (self installed tumbler method)
Varget initial load 42 grains good load
Varget second load 44 grains primers flat (as in fill up the primer pocket and begin to flow around the firing pin..flat) and bolt difficult to open.  Obviously I stopped right there.  The max load is 46 grains so I am 5% below max with a moly bullet.  I pulled the bullets and verified the powder charge, it is correct.  I checked the rifling depth of the rifle and the oal was well clear of the rifling.
The 44 grain load is a compressed load, could this lead to a spike in pressure?  I can seat the bullet much further out towards the lands and grooves.  Any ideas or help would be appreciated, I love the .308 round and would like to continue loading it, I don't want to destroy my gun or my person.  Thanks
Link Posted: 1/23/2009 7:05:16 PM EDT
[#1]
If you can seat the bullet farther out, try it.  But back off to 42 grns. and begin working up again on the powder.

I seat the bullets just short of touching the rifling.  I seat a bullet a little long and then slowly/softly attempt to chamber it.  If it's way too long you'll feel it.  If its almost there but still hitting the lands, you can see it on the bullet.  Polish the marks off with some real fine steel wool and seat the bullet a little deeper and try it again.  If the bullet hit the lands you can see the marks on the bullet.  Keep repeating till you get the bullet seated just a little short of the lands.  Of course, make sure it still fits the magazine unless you are single loading it.

Having the bullet farther out could lower the pressure if it is far enough out.  And keep an eye on those primers, too.
Link Posted: 1/23/2009 7:29:39 PM EDT
[#2]
On my other two rifles I seat the bullets .005 from the rifling, and have never had a pressure problem even with max loads that is why I'm mystified
Link Posted: 1/23/2009 8:06:54 PM EDT
[#3]
There is a phenomena known as a secondary pressure spike in barrels longer than 20". Even factory loads do it and
pressures can double saami specs. Do some reading on it. When you send off a load to a lab to check it they won't
even record the secondary pressure unless you specifically tell them to. It's been long denied by ammo manufacturers
but there has been too much independent testing to deny it anymore. Change powders, and bullets if you have too.
Link Posted: 1/26/2009 11:37:33 AM EDT
[#4]
bump for a few more answers
Link Posted: 1/26/2009 12:24:26 PM EDT
[#5]
This seems to be happening to me as well in my Rem 700 with factory barrel. My 45 gr load of Varget was showing some flattened primers. The throat in the factory tubes are pretty long and I'm sure I'm not jammed into the rifling. I cant figure it out

FIXIT you may be on to something here. I do have a 26" barrel, Hodgdon testing used a 22" I believe
Link Posted: 1/26/2009 4:50:19 PM EDT
[#6]
Hornady's Max load with Varget/168 is 44.0 gr @ 2600 OAL 2.800" 22" bbl

Nosler's Max load with Varget/168 is 46.0 @ 2820 OAL 2.810" 24" bbl

Speer's Max load with Varget/168 is 46.0 @ 2746 OAL 2.800" 22" bb

With so many sources indicating that 44 to 46 grains of Varget with a 168 Match bullet should be on the safe side, it makes me wonder too.
First of all, I would discount the compressed load being a factor if your bullet is seated out to at least 2.800" COAL.
And since you are not using a low charge of a very slow burning powder (i.e. 4350 or slower) I really don't think there is any secondary spike issues involved, especially with the short powder column and modest capacity of a .308 sparked with a normal LR primer.

I am wondering if the Moly is a culprit.  It is the only unusual addition or change that you seem to have done, and I have noticed the Moly craze seems to have faded for some reason.
 
I would be very interested as to what your load chronographs.  Velocities that are unusually high, by a factor of 50-100 fps indicate higher pressure.  Shooting some factory 168 Match loads and then shooting your 42 grain load would indicate how close you are to factory velocity and indirectly, pressure.
If your rifle likes 42- well, that is fine too, no use chasing the dragon.  
Link Posted: 1/26/2009 4:53:16 PM EDT
[#7]
The secondary pressure spike sounds interesting although I have never heard of it or seen a pressure curve showing it. . .

I would look at your headspace rifle vs. loaded round.  When a cartridgeis fired the case expands to touch the chamber sides.  Then the primer is blown back out of the primer pocket, closely followed by the case head.  Excessive headspace will cause the primer to get excessively mushroomed and give a false pressure sign.  Reading primers assumes near 0 headspace.

Use a Hornady LNL headspace gage or similar to measure fired cases and sized cases.  Sized cases should be .003 - .005" shorter than fired.  For an accuracy type bolt gun load, this can be more like .001 - .002".
Link Posted: 1/26/2009 5:34:37 PM EDT
[#8]
Link Posted: 1/26/2009 6:01:49 PM EDT
[#9]
Not an expert am I, but could the compressed load be pushing the bullet out over time and putting the bullet closer to the rifling resulting in higher than normal pressures? Maybe load a test round and measure it for "growth" over a few days/weeks.
Just a WAG.
Link Posted: 1/26/2009 9:12:22 PM EDT
[#10]
I would suggest breaking in the new Savage barrel with the 42 grain loads.  Setting up your scope, getting best group sizes, chronographing, etc.   Then about 200 rounds later, after going through the recommended break-in procedures, return to the 44 grain load.    Varget is normally hard to beat for a good stable powder.  However, as Aero-E points out, the burn rate and energy can vary a little from lot to lot.  So, do your load work-up campaign from the same container.  

I have a new Savage .243 barrel, and notice the chronograph speeds slow up from start to finish for a 5 to 10 round run.  I still get some copper residue from the bullet jacket after 50 rounds.
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