Savage m12 F/TR

[ftrrookie]

Before I get to the question I need to say that I'm new to the sport and I only have a Remy 700 for comparison. Also, the gun shoots extremely well, far better than I'm capable of, so this is more for my personal knowledge base than anything else.

The m12 F/TR is chambered in .308 win. When I measured the chamber using 175 SMKs I got 2.224" Base to Ogive just touching the lands. I measured it multiple times and used an average to arrive at that number. When I load a round at that measurement I get a COAL of 2.801". As I said, my only comparison is my m700 chambered for the same round and a round loaded to 2.800 will give me a jump of .103" to the lands.

Is having such a short chamber/throat common in Savages? Or maybe just their Target Rifles? I'm not complaining, with 40.6 gr of Varget and seating the 175 .020 off the lands I'm getting an average velocity of 2636 and if I want to push it 41.5 gr will bring it up to 2696 fps. I start seeing pressure signs at 42.5 (shiny ring on base). By comparison the Remy won't break 2600fps until 43.3 gr and really shoots best at 44.1 gr.

 

[Multitoes]

Jay,
I have purchased several Savages lately ; mostly for donor actions.
I have found that they do have throats that are a reasonable length -- unlike my 700's, even ones that are many years old.
None of these rifles have throats that are too long for any bullet (except maybe something like a 55 Gr. in a.243 Rem) to reach the lands and rounds all fit in the magazines.

 

[broncman]

I have one and it has a throat just a touch longer, not much.
Shiny ring?? The bolt head will sometimes leave a shiny ring on some brass when I rotate to open on a fired case.

Ejector mark and primers are what I look at. I was running 175 SMK with more varget than what you listed with no issues and in the mid 2700 range...

 

[mao0720]

FTR rookie, what type of brass are you using? Because with Lapua brass, I dont think you would be seeing pressure signs that early with varget. Might be able to get that thing moving a good speed and find the next node up if you use Lapua brass (thats if you're not using it already).

 

[ftrrookie]

I'm using lapua brass. I've wondered about that shiny ring because when I look at the primers from cases fired with 40.6gr and one with 42.5 they look the same. It's just that the ring doesn't appear until I go over 42.5.

 

[mao0720]

I dont want to pull this thread off topic, but if you post a photo of the case heads in question, we might be able to help you out.

 

[fm1947]

I had a savage that would blow primers out at loads that most could shoot no problem, I also had a target in 6mm br when most load 30 grs varget I couldn't presure at 29GR, but it shot good

 

[ftrrookie]

mao I've already run them through the tumbler but I'll put together a couple and post when I fire them.

fm1947, I don't care how much powder is in the case as long as I get the accuracy and the speed I want. And I am. Heck the way I look at it I'm saving powder on every round fired compared to my M700.

On another note I picked up another M12 F/TR yesterday. This one chambered in .223 rem. Looking through the loading manuals both Hodgdon and Sierra spec the COAL of this cartridge loaded with 80 gr SMKs at 2.550". So I put together a dummy rnd this length and you guessed it, it's too long for my chamber. After I closed the bolt on it and extracted it it was 2.505" long. So just like my 308 I'll measure the chamber/throat length and start out with a .020" jump and go from there.

 

[fm1947]

You said (So I put together a dummy rnd this length and you guessed it, it's too long for my chamber. After I closed the bolt on it and extracted it it was 2.505" long. So just like my 308 I'll measure the chamber/throat length and start out with a .020" jump and go from there. ) My point exactly , I couldn't run the same as others due to case capacity bullet would not go long , there fore I had to much pressure at short length, just work your way up in powder.