.223/77TMK for semi, results

[1168]

I haven't seen Wolf primers available for a LONG time. Thought maybe they weren't even made anymore.

Didn't see much of a noticeable difference using Wolf primers compared to the others I tried a few years back in a head to head primer test using about 9 or so different primers.

What other primers did you find you liked for 5.56 in that testing?

[lsllc]

What are you measuring those velocities with?
That seems a little high with a 16' barrel.

Magnetospeed and a Chrony


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[ABNAK]

So what is the consensus on the 77gr TMK loaded by Black Hills to 5.56 pressure? Not talking accuracy-wise, but terminal performance. Does it hold much over the Mk262 in that department?

[fedupflyer]

Magnetospeed and a Chrony


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What Mk262s are you using?
Your velocities in a 16' are higher than my 18' and about 100FPS higher than my 16' measured with a Magnetospeed.

[lsllc]

That was Black Hills. I am shooting suppressed. It was 10 FPS slower than out of a 20”


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[mark5pt56]

What Mk262s are you using?
Your velocities in a 16' are higher than my 18' and about 100FPS higher than my 16' measured with a Magnetospeed.

Remember, every barrel is different, so many variables. Although you would need the same ammo or components, a chronological helps to track changes. One example of barrels, a class, two rem 700's one number apart, same case of ammo, one required .4 more elevation once distance mattered.

How many rounds on your barrel and conditions it has lived in?

[mark5pt56]

Hardly scientific, but enough for me to use 205m's I did a test some time ago and this gun seemed to like them. I've shot other comparisons and the primers are close but bullet or powder may push one closer to the top.

LMT 20"(same gun in OP, same lot of powder, but with SMK, same charge weight)

2 groups of 5, hour or so apart, one single loaded, the other from magazine.

205M-.6
BR4-.735
CCI400-1.005

[mark5pt56]

I don't have 262 velocities, the 2760 seems in line. The lot of Magtech 77's was 2700 from an 18" I had. Same gun had 2690 from a 22.8 H4895 and 75 Hornady BTHP.

[ABNAK]

I don't have 262 velocities, the 2760 seems in line. The lot of Magtech 77's was 2700 from an 18" I had. Same gun had 2690 from a 22.8 H4895 and 75 Hornady BTHP.

I can tell you this much: I had a thread a while back in the AR forum where I was testing various 5.56 ammo in a new Hodge barrel (with the slightly smaller gas port specifically for M855A1) with an LMT EBCG. One of the rounds I tested was the IMI "Razor" 77gr Mk262 clone. I had an overall failure to lock back on an empty mag about 20% of the time with the ammo I used, except for the "Razors", which locked back 100% of the time. Even M855A1 (with it's higher pressures) had a few failures to lock back. Bottom line? That IMI "Razor" is some HOT ammunition, so I'd be curious to see some chrono data on it.

[ST911]

For both 262 and the (BHA) 5.56 77 TMK I get low to mid 2600's from most 16" unsuppressed barrels. Variety of chronos.

So what is the consensus on the 77gr TMK loaded by Black Hills to 5.56 pressure? Not talking accuracy-wise, but terminal performance. Does it hold much over the Mk262 in that department?

TMK is more (varmint-like?), shorter neck with rapid and violent upset, shallower overall penetration. Accuracy is excellent, higher BC, flies well.

What Mk262s are you using?

There's only one. Everything else is a 77 SMK. Just sayin'.