Light vs Heavy and Extreme Spread

[deertroy1]

I'm noticing I cannot get consistent velocities when shooting light bullets in my 6mm Rem. It is a McGowen barrelled Savage. I'm starting to think it's because of the firing pin assembly as it also gave high ES when it was new as a 243 Win. Unfortunately it has the one piece firing pin. Firing pin protrusion is good at 0.053". It severely craters primers with even mild loads. I was told this is a result of too sharp a firing pin tip. I made it more blunt and it helped with the cratering but did not eliminate it. I made it more blunt and it wouldn't fire. I put it back and it fires but the cratering is back.
I recently tried some 100gr bullets with RL-22 and ES was down in the low 20's and teens. With bullets 75gr and under it's anywhere from 50 - 100 fps for five shoots. Accuracy isn't all the great either.
I've tried all the little things like different brass, different bullets (Nosler, Berger, Sierra, Hornady), different powders (H4895, Varget, RL-15, RL-16, Staball 6.5, H4350, Big Game, Hunter, W760, etc.), different primers, weighing cases, cleaning up the necks, etc.
I was wondering if anyone else has experienced having difficulty getting low ES with light for caliber bullets?

 

[RockyMtnMT]

How is your case fill? We seem to do best if we can reach pressure and 100% case fill at the same time. Also we will see big spreads if we are using a powder that is too slow so that the some of the powder is exiting the barrel before it is burnt.

 

[deertroy1]

I've tried just about every powder I can think of. There isn't many powders that will give near 100% case fill and near max pressure in the 6mm Rem with 75gr and under bullets. RL-17 and H4350 does best at doing what you describe but I tried both to no avail. RL-16 and Ramshot Hunter comes close but fills the case before max loads are reached. Neither worked.

 

[tim_w]

If 4350 is not working that's wierd and could still be the firing pin primer issue. Can it be replaced?That powder is the gold standard for the 6 remmy. I would think IMR4350 should give close to full load maybe not hmmm

You can try H414, VV N160. IIRC the load density of H414 should fill up the case for light bullets. Do not have QL handy so check these for load density. Have you tried CCI#34 primers as they tend to have harder cup and seat deeper. You could try some slower bulkier powders just do not go too slow. What about rel19?

I am assuming youve covered all the normal load workup steps to lowering ES? Not too much neck tension. Change seating depth. Figured you have hut had to ask

Hey how many different types of lower weight bullets have you tried?

How many rounds thru the barrel?

 

[Frog4aday]

<snipped stuff> Unfortunately it has the one piece firing pin. Firing pin protrusion is good at 0.053". It severely craters primers with even mild loads. I was told this is a result of too sharp a firing pin tip. I made it more blunt and it helped with the cratering but did not eliminate it. I made it more blunt and it wouldn't fire. I put it back and it fires but the cratering is back.

I'm confused by this. Did you put in a NEW firing pin, or are you still using the one you've modified twice now? My gut says get a new, untampered with firing pin & fresh spring and try again. Inconsistent ignition could be the issue.

Also, Savage bolt actions don't like a lot of torque on that rear screw. Perhaps back that off to 10 or 15 ft/lbs and see how it shoots?

 

[Turbo2160]

If 4350 is not working that's wierd and could still be the firing pin primer issue. Can it be replaced?That powder is the gold standard for the 6 remmy. I would think IMR4350 should give close to full load maybe not hmmm

You can try H414, VV N160. IIRC the load density of H414 should fill up the case for light bullets. Do not have QL handy so check these for load density. Have you tried CCI#34 primers as they tend to have harder cup and seat deeper. You could try some slower bulkier powders just do not go too slow. What about rel19?

I am assuming youve covered all the normal load workup steps to lowering ES? Not too much neck tension. Change seating depth. Figured you have hut had to ask

Hey how many different types of lower weight bullets have you tried?

How many rounds thru the barrel?

This is a little left feild but it my 20 bits. Take it as u will. dont laugh to hard at this.. I do know the the powders I'm going to say are the same.. I whent from H414 to W760 and dropped both my Ext &STD. Dont ask my why or how but the papper shows it and so does the lab radar

 

[Kansaswoodguy]

Gun doesn't like lite bullets move on

 

[Deputy819]

What is the rate of twist on that McGowen?

 

[deertroy1]

What is the rate of twist on that McGowen?

1-9"

 

[Deputy819]

What kind of chronograph are you using?

 

[deertroy1]

What kind of chronograph are you using?

Oelher 35P. It's not the chrono as several of my other rifles check out fine. I've also checked it against my older M33 and they both agree.

 

[Deputy819]

My target rifle is a .243, but actually started life as a 6mm Remington. It's got a stainless steel Douglas barrel w/1-9" twist, straight taper 1" diameter. 6mm Remy chamber was cut with a brand new Manson reamer and for whatever reason I never could get consistent groupings/velocities out of it either (there's an older thread of mine somewhere on here about it). I tried several powders, several bullets, and several primers and I finally had to just give up. Had my gunsmith re-chamber it to .243 Winchester with a reamer he had previously used to cut 3 chambers with and it's now the most precisely accurate (and consistent) rifle I have. I hope you get yours figured out, brother!

 

[tim_w]

This is a little left feild but it my 20 bits. Take it as u will. dont laugh to hard at this.. I do know the the powders I'm going to say are the same.. I whent from H414 to W760 and dropped both my Ext &STD. Dont ask my why or how but the papper shows it and so does the lab radar

I totally believe that. Change in powder can effects lots of things.

 

[deertroy1]

I totally believe that. Change in powder can effects lots of things.

I agree. But I've tried, H4350, Varget, Big Game, Hunter, Staball 6.5, RL-16, RL-17, RL-15, H4895 and W760.
I tried these with 55gr Nosler, 55gr Sierra, 58gr Hornady, 65gr Berger, 65gr Hornady, 69gr Berger, 70gr Sierra and 75gr Hornady.
I get mostly groups between 0.75" and 1" at 100 yards with the occasional group less or more. However, when I find something that seems promising it isn't repeatable.