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Discussion Starter · #22 ·
Quick Range Trip

The first M14 .338 Federal was born yesterday and I had a chance to do a quick range trip today for velocity and function testing.

I necked up .308 brass by running it through a Redding FL sizing die. I have settled on Western Powders TAC. It's a very easy loading powder that works extremely well in .308 and has shown very good velocity in the .338 Fed. The velocity spreads were exceptional.

Due to the larger bore diameter and powder burn rate, no gas system modifications are required or recommended.

Function was 100% and all rounds were loaded from the magazine. Four (5) shot groups were fired at 100 yards. Recoil was significantly less than expected. I fired the rifle without a muzzle break and it was very manageable. In fact, I fired my F-class .308 right behind it and recoil was much sharper with the 17.55 pound match rifle.

Following is a short list of what I've captured to date. My magneto speed was only getting 4 out of 5 rounds to register on each five shot group.

1. 44.5 Grains of TAC, BR2 Primer, FC 308 Brass with 200 grain Hornady SST. OAL 2.846" Ogive seating depth 2.077". Velocity 2480 (First shot new bore) 2502, 2495, 2498 Avg. 2493 SD 9

2. 44.5 Grains of TAC BR2 Primer, FC 308 Brass with 200 Speer Hot Core, OAL 2.816" Ogive seating depth 2.369" (Touching Lead) Velocity 2491, 2464, 2493, 2482 Avg. 2483, SD 13.2

3. 44.5 Grains of TAC, BR2 Primer, FC 308 Brass with 215 Sierra GK SBT, OAL 2.834, Ogive Seating Depth 2.349" (Touching Leade) Velocity 2475, 2469, 2464, 2462, Avg. 2467 SD 5

4. 42.0 Grains of TAC, BR2 Primer, FC 308 Brass with 225 Hornady SST. OAL 2.870" maximum length to fit mag, Ogive seating depth, 2.264" ~ .035" off lands. Velocity 2307, 2304, 2313, 2312 Avg. 2309 SD 4.

Two velocities surprised me. The Sierra is 15 grains heavier but was within 20 fps of the 200 grain. Number 4 is a middle of the road load for the 225, but it outperformed the book velocities published by Western Powders in 2016.

This round in the M14 is capable of delivering some serious energy downrage.

My plan is now test for accuracy at 100, 200 and 300 yards.
 

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Good info Jon.
I have some 200 gr speer hot core with 8208xbr and H335.
In LC brass and WLR primers.

Looking forward to some more range reports.

Are the headspace numbers the same as .308/7.62?

pg
USA2
 

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Discussion Starter · #24 · (Edited)
Headspace

Are the headspace numbers the same as .308/7.62?

pg
USA2
No, the intersection is called out at a different diameter/datum and as such is shorter by about .025".

The .338 Federal has a broader variance than .308 Win. I believe it has .010" between max and min.

The test fire was your upper by the way. First in, first out!

Here is a range card that compares the .338 215 Sierra GK to the .308 Sierra 175 MK. The .338 holds its own on the ballistic end and significantly outperforms with regard to downrange energy.

Top is the .338 Federal with the 215 Sierra, at a muzzle velocity easily obtainable in the M14. The lower table is the 175 Sierra MK at 2530 fps.
 

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No, the intersection is called out at a different diameter/datum and as such is shorter by about .025".

The .338 Federal has a broader variance than .308 Win. I believe it has .010" between max and min.

The test fire was your upper by the way. First in, first out!

Here is a range card that compares the .338 215 Sierra GK to the .308 Sierra 175 MK. The .338 holds its own on the ballistic end and significantly outperforms with regard to downrange energy.

Top is the .338 Federal with the 215 Sierra, at a muzzle velocity easily obtainable in the M14. The lower table is the 175 Sierra MK at 2530 fps.
It's alive?
Hey everyone, it's alive!!

Okay so probably best to get a .338 comparator insert and a .420 insert for headspace dimension.

Thanks for the range card data, that gives me a good baseline to start from.

Need to order some Sierras also.

pg
USA2

Check will go out tomorrow!
 
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