180s

A

akinswi

New member
I found a couple of boxes of Noslers Combined Technology Ballistic Silver Tip .308 180 grain bullets around my bench.

Ignoring the warning from The CMP about bullets heavier than 170 grains in M1, I went to my hornady manual. Now they dont list 180, but list 178 (close enough)

So I started at

43.6
43.9
44.2
44.5
44.8

I will shoot 25 first and if they shoot ok will finish

45.1
45.4
45.7
46.0
46.2

They list maximum at 46.7 with IMR 4064 so I want to be .5 grains under max since using No 34 primer. I did use Noslers Recommended COL of 3.30

Im really interested too see how these do
 
Considering the old National Match M1 Type bullet was 174.5 grains with -3.0 grains tolerance (most I've measured have been about 174 grains in the M1 Type, though I've weighed M1 Ball bullets (same design, but with a crimp cannelure) as low as 172 grains), I think the 170-grain limit is timid. I've shot a small mountain of Sierra's 175-grain SMKs because they are closest to the old match bullet. The heavier the bullet, the bigger the gas impulse is at the gas port, so some may fear damage to an old or marginal operating rod from heavy bullets, but that's an argument for staying at 150 grains. But if you are running the Garand Gear plug, you won't see an issue even with a worn op-rod.
 
Unclenick said:
Considering the old National Match M1 Type bullet was 174.5 grains with -3.0 grains tolerance (most I've measured have been about 174 grains in the M1 Type, though I've weighed M1 Ball bullets (same design, but with a crimp cannelure) as low as 172 grains), I think the 170-grain limit is timid. I've shot a small mountain of Sierra's 175-grain SMKs because they are closest to the old match bullet. The heavier the bullet, the bigger the gas impulse is at the gas port, so some may fear damage to an old or marginal operating rod from heavy bullets, but that's an argument for staying at 150 grains. But if you are running the Garand Gear plug, you won't see an issue even with a worn op-rod.
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Nick,

Thats why I went with IMR 4064, should be easier on the gas system vs IMR 4895. After shooting them. They didn’t do better than my match load with 168 SMKS.

Load development is done. Sticking with IMR4895 and 168s. I will just adjust seating depth as the throat erosion increases once the groups open up. I can already start too see some when I cleaned the bore this after noon with the bore scope after 500 rds

You can see small ramps, digging into the grooves where the leade starts, Im assuming this is erosion, there is very little to no fire cracking probably due to I have never got the barrel really hot
 
It may take 2,000 rounds or more before you see heat stress cracking in the '06. It's caused by combustion gases at the peak pressure and temperature point in the burning curve heating the surface of the steel faster than the heat can penetrate more than a couple of thousandths into the steel, resulting in a temperature differential between the surface and the substrate that creates a lot of stress.

Regarding the bullets, the new 169s should give performance similar to the 175s at long range but with a little less gun stress. How their accuracy compares at short range, I am still waiting to get past my knee replacement rehab to find out.
 
Unclenick said:
It may take 2,000 rounds or more before you see heat stress cracking in the '06. It's caused by combustion gases at the peak pressure and temperature point in the burning curve heating the surface of the steel faster than the heat can penetrate more than a couple of thousandths into the steel, resulting in a temperature differential between the surface and the substrate that creates a lot of stress.

Regarding the bullets, the new 169s should give performance similar to the 175s at long range but with a little less gun stress. How their accuracy compares at short range, I am still waiting to get past my knee replacement rehab to find out.
Click to expand...
Are you going try them in your current barrel? or will you still wanting to put a new barrel on?
 
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