29.5 grains of Varget for 6mmbr, to much?

[LR_Shooter]

I made few loads for my new rifle and new caliber in 6BR. I used 29.5 grains of Varget and 105 grain Scenar, I think its to hot! Take a look:

 

[Frankr]

what primer ?

 

[LR_Shooter]

CCI 400

 

[jo191145]

CCI 400

Wrong Primer.

CCI 450
CCI BR4
Rem 7.5

even the Fed205 M should work better.

Try those if problems persist post more pics.

While 29.5 may be too hot in your rifle usually its not.
A thin primer such as the 400 will not accurately tell the tale

 

[LR_Shooter]

loads with 28.5 grains of Varget also show pressure, but not like the ones in the picture.

 

[jo191145]

loads with 28.5 grains of Varget also show pressure, but not like the ones in the picture.

With the CCI 400 I'm sure it does.
That primer is not designed to be operating at 6BR pressures.

 

[ridgeway]

Yep, primer. Run the 450's or Wolf SRM.

 

[Frankr]

well you might try a cci BR4 or cci 450. my self i would back off a half grain of powder with a cci 450 primer and work back up. not that familur with norma brass or LA105's.
would check loaded round neck dimensions as to what the chamber is.
thats all the help i can offer.
but yea they look hot.. dont know what kind of rifle but fireing pin hole fit can cause primer cratering like that, and i had a load once that a gunsmith said.your way to hot . and i said no im not,you install this holland oversize fireing pin and fit it to the hole. well i talked him in to doing it.I dont think he did a great job but it took about alittle over half of the cratering away. still what i called(tited up) the primer alittle bit. shot that load for years.

 

[LR_Shooter]

I'll check with my local suppliers see what they got available, I use CCI 400 for my 223 with 27 gr of Varget, but never seen anything like this before. CCI 450 and BR, they rare in my back yard, usually its CCI 400, Federal, Winchester, Remington and no Wolf.

 

[Obtunded]

That's weird. Depending on the batch of Varget and the gun, I personally use loads up to 31.6 grains and I know shooters up to 32 grains.

I agree that the primer/bolt combination would be the prime suspect. Something with a big sloppy firing pin hole like a Savage almost certainly requires a good tough primer like a CCI 450/BR4, but I wouldn't even start my ladder test with a charge weight that light!

Is this a tight necked chamber with non-turned brass? Lapua bullets are very undersized, so it shouldn't have anything to do with the or the bore size...

Ian

 

[LR_Shooter]

Here is what bolt head looks like, not sure if you can see, but it looks like a dimple area around firing pin hole. Also I think the hole drilled for large primer firing pin and I think 6br should use small primer firing pin so the hole should be smaller.

 

[LR_Shooter]

its a factory Savage, no idea what chamber they use. I never had 6br before, this is a replacement for my 260 and that's my first load for it.

 

[LR_Shooter]

here is some pictures for comparison, the one on the left is from my hunting Savage uses LP, the one in the middle from 6BR and the right 223 Rem and the hole looks much larger, so the firing pin

closer look

 

[jhord]

Anybody know what the Norma case capacity is vs. Lapua? That could be it?

 

[LR_Shooter]

I walked in my local store to check on primers, the only thing they have are CCI 400, Federal 205M and 205, I will check with others this afternoon. After doing more research, I think it has to do with small firing pin used by Savage on both LP and SP and not having Small Rifle Magnum Primers.
By the way had anyone done this http://bulletin.accurateshooter.com/2007/07/tech-tip-bushing-firing-pin-holes-for-performance/
I think this can be good solution to what I have.

Just found this, I think its good example.

http://benchrest.com/showthread.php?33090-Anyone-know-a-good-smith-to-bush-a-Remington-bolt.

 

[6BRinNZ]

LR_Shooter - I have a Howa with a standard firing pin hole. I used to use CCI400s but they are just too thin, I am not suprised that you had a lot of cratering with that load. It probably isn't generating excessive pressures for a 6BR case, just the primer is too thin against the firing pin hole. What FPS are you generating? If you are over 2900 then it would be a hot load....this is a generalised statement.

In comparison my Barnard P in 6BR with the small firing pin hole won't crater the primer unless I am absurdly hot...I have achieved 32.5grns varget and 105 A-max using a CCI400 and it just started to crater.

I use the CCI450 in my Howa now, it lets me run reasonable pressures and MVS without the worry of holing the primer.

Personally I don' think the primer is a good indicator of pressure as it is too easily manipulated...i.e. use a small firing pin hole and suddenly a "hot load" becomes normal...use a thicker cup and voila a "hot load" is ok again...

One point you may want to check out...is the bullet seated into the neck shoulder area...if so then you could well have donuts forming and gripping the bullet excessively, this will cause excessive pressure spikes and cratering on previously ok loads.

 

[LR_Shooter]

One point you may want to check out...is the bullet seated into the neck shoulder area...if so then you could well have donuts forming and gripping the bullet excessively, this will cause excessive pressure spikes and cratering on previously ok loads.

Yes, bullets have to be seated into the neck shoulder area, I have no other way to seat them, freebore on this rifle needs to be extended, this is factory Savage 1:8 twist, I think they used same reamer as for 1:12

Using 105 A-max what max oal do you get, in this chamber I just measured 2.330" or 1.804" using ogive, that leaves about 0.245" freebore.

 

[Steve Blair]

I just measured 2.330" or 1.804" using ogive, that leaves about 0.245" freebore.

My reamer with .104 freebore provides OAL 2.335", just touching, with 105 A-Max. It sounds like your freebore is about .110, the same as my Savage 6BR factory barrel.

Savage bolt heads often show cratering due to sloppy firing pin fit. Mine had both sloppy fit and a pronounced dishing around the hole that caused fired primers to bulge outward. Both bolts were sent to Greg Tannel at Gre-Tan who bushed the bolt heads and turned the firing pins to a smaller diameter. End of problem and I now have more consistent ignition.

http://www.gretanrifles.com/

I also agree with the other posters to ditch the 400s. Use CCI BR4, CCI 450, Wolf KVB-5.56M, or Remington 7½. The CCI 450 is especially tough.

 

[LR_Shooter]

Thank you Steve! I must calculated freebore wrong, I only took measurements using OAL gauge and measured ogive length with bullet comparator, which I thought supposed to indicate bullet touching lands. About CCI400, I already ditched them, will shoot my 223 with them and I bought some BR4!

Steve, what groups do you get with your factory barrel? My was tested at factory using Lapua 105 gr ammo 0.64"@100, with whatever loads I had so far it shot 0.6" on average, smallest group I got from it 0.52".

 

[Steve Blair]

Once I found what it wanted, groups were in the .3-.4 range. The barrel never did clean well, even after ~675 rounds fired. That rifle (for now) wears a nitrided .22-250 barrel that is shooting and cleaning very well after ~250 rounds.