Cold bore load results

[cjmac]

Well this is what I cam up with . In the Sierra book , 43g of varget under a 150g Sierra btsp gave 2700fps . Looking at old notes on other rifles that's where my 308s tend to like it most so I tried it on this factory gun .
43g varget
150g btsp
Book length from Sierra
And light crimp
5 shots each 20mins apart .
Then a 2 shot group on cold bore
At 100 yards , the orange dot is 1.5in

 

[cjmac]

Well this is what I cam up with . In the Sierra book , 43g of varget under a 150g Sierra btsp gave 2700fps . Looking at old notes on other rifles that's where my 308s tend to like it most so I tried it on this factory gun .
43g varget
150g btsp
Book length from Sierra
And light crimp
5 shots each 20mins apart .
Then a 2 shot group on cold bore
At 100 yards , the orange dot is 1.5in

Let cool and pulled a dry bore snake through it sent 3 rounds back to back and this was the result. Orange dot is 1.5in .

 

[Coyotefurharvester]

Wind at your 7 or 11? Or was the first rd after the snake the high right poi?

 

[cjmac]

Wind at your 7 or 11? Or was the first rd after the snake the high right poi?

Wind was more about 5 or 6ish . It was shifting a lot today
The high round was after snake . I did this 3 more times .
I ran the snake before each group. Shoot a group wait 20 mins till cold . Shoot another group and so on... shot 4 groups , all 4 where like this or better !

 

[cjmac]

The last 2 groups I shot where inside the 1.5in orange ! . The bore snake i guess pulled enough out the barrel to help it ?

 

[JFrank]

So, no testing ? Just used a load that worked in a different rifle and called it good enough ?

 

[Doom]

The last 2 groups I shot where inside the 1.5in orange ! . The bore snake i guess pulled enough out the barrel to help it ?

It sounds like you are hung up on three shot groups. In post #2 is the high right shot the first shot each time after the snake? If it is then the rifle is telling you to not use the snake or shoot a fouler before going to the field. If it is the third (in each case) you probably are either seeing fouling OR temperature on a thin barrel.

 

[cjmac]

It sounds like you are hung up on three shot groups. In post #2 is the high right shot the first shot each time after the snake? If it is then the rifle is telling you to not use the snake or shoot a fouler before going to the field. If it is the third (in each case) you probably are either seeing fouling OR temperature on a thin barrel.

If i remember correctly yes the high one was first after the snake . I did try to slowly shoot a bigger group but it just got to hot and would open up after about 4 or 5 shots . I'm going to try it again next weekend in different ways .
Snake then shoot 1
No snake then shoot one
And see how the temperature drop will effect it also it's supposed to be about 30

 

[mikecr]

Book length from Sierra won't get it. Need to find optimum CBTO.
Changes to fouling and temperatures won't work for cold bore testing.
The 20min shot rate may work for the testing but that is nowhere near cold bore.
So when your testing at 20min is completed, you need to validate true cold bore.
Also, if you're shooting off a bench rest,, then unless you hunt from that bench rest, you're wasting your efforts.

Not easy huh?
Whole lot more difficult to get a gun shooting field accurate, than simple hot precision.