Load data for 77 TMK in 223

[philcox]

What barrel/rifle?

Edited my post.

 

[Schmo]

Gotcha. I feel you’re a little slow on the velocity side. Tac gives really good velocity with the heavies, and I think is a little more stable than CFE. Another one I’m testing and impressed with is Alliant Power Pro 2000-MR. I also have some TS15.5 I might try.

 

[Schmo]

Even with the 18”, I would expect 2700-2800.

 

[philcox]

Gotcha. I feel you’re a little slow on the velocity side. Tac gives really good velocity with the heavies, and I think is a little more stable than CFE. Another one I’m testing and impressed with is Alliant Power Pro 2000-MR. I also have some TS15.5 I might try.

I have 8 lbs of CFE, so kind of "committed" to that at this point. I am using CFE for my 55g Berry load. New barrel, so may get to 2700 at some point.

 

[Schmo]

Gotcha

 

[swavescatter]

24 gr varget seated at mag length gets crunchy but shoots well @ 2750fps ish
23.7 gr xbr 8208 seated at mag length meters well and gets more velocity @ 2800+ ish fps

What barrel, primers, brass, COAL are you getting 2800+ with XBR? I'm quite a bit slower at about 2766 fps out of a 22" Tikka, Starline brass, 2.32" COAL and Fed 205M primers. CCI450 are about 10fps slower surprisingly.

Maybe pressure really starts spiking around 23.6gr? This was also pretty cold near freezing this morning though...

 

[swavescatter]

Doing load work-up for a Tikka .223 Ranch with 16" standard lite contour barrel. Using 77 TMK and CCI 400 Primers.

Initially tried TAC and CFE 223 which I had on hand. TAC gave best veloicty at 2670, would get split groups with 80% being in a nice tight cluster and the other 20% as fliers 0.5-1" from the main group. CFE 223 produced good groups but I could not get good velocity out of it. 2580 with book max loads and it is quite temp sensitive.

This last weekend picked up n540 which on initial testing is awesome stuff. Great accuracy and the by far the most consistent velocity (low SD). Load is 23.8 n540 with 77 TMK seated to 2.32 in Starline Brass. Produced multiple groups like the one below. Not sure what the temp stability of this powder is but it has to be better than CFE 223.

Also tried Benchmark which is a bit fast but I had on the shelf and it did well too accuracy wise. 0.9" for ten shots with 2595 fps.

View attachment 801139

What velocities did you get with your n540 load? Also, if you could share the whole recipe that would be great (COAL, primer, brass)...

 

[swavescatter]

I'll be doing some more testing, and inch my way up to 23.8 grains with the next ladder. Also fill out the BR4 data.

Tikka T3X Lite 22.4" Barrel with OCL Polonium 556 Can
77gr TMK's, 8208 XBR, 2.32in COAL, Starline once-fired brass, 2 thou neck tension

 

[philson208]

What barrel, primers, brass, COAL are you getting 2800+ with XBR? I'm quite a bit slower at about 2766 fps out of a 22" Tikka, Starline brass, 2.32" COAL and Fed 205M primers. CCI450 are about 10fps slower surprisingly.

Maybe pressure really starts spiking around 23.6gr? This was also pretty cold near freezing this morning though...

I don't think your numbers are way off of mine. 2801 was my recorded high and 2777 my low out of maybe 5 shot string with 23.7 xbr over a magnetospeed. unknown primers, most likely pmc brass, coal 2.260, out of a 22" stainless t3x barrel. My range data is taken from early spring in Idaho, 50's and sunny. In all fairness 2800fps is most likely the high end of the spread.

 

[Mulyhuntr]

Surprised H4895 hasn't been mentioned more

 

[mustelid_master]

Surprised H4895 hasn't been mentioned more

I think availability is the issue

 

[rdp123]

Curious if anyone knows why Sierra book max for 77 TMK over Varget (22.1g) is so much lower than Hodgdon (23.7) or Hornady (24.5ish) for similar sized and shaped bullets. It’s also lower than Sierras own book max for gas guns, though I thought gas guns had lower pressure tolerances than bolt guns.

I’m new to reloading and not wanting to blow up my gun or myself, so I’m going by the book (and thrilled with the results so far) but also a little confused about the contradictory info. I called Sierra and they didn’t have any explanation for the divergence. It seems like people here are blowing well past the highest book maxes I’m seeing, at least in Tikkas. Is this because Tikkas have higher than average pressure tolerances? Or are people relying more on observed pressure signs than published book maxes?

 

[KyleR1985]

Curious if anyone knows why Sierra book max for 77 TMK over Varget (22.1g) is so much lower than Hodgdon (23.7) or Hornady (24.5ish) for similar sized and shaped bullets. It’s also lower than Sierras own book max for gas guns, though I thought gas guns had lower pressure tolerances than bolt guns.

I’m new to reloading and not wanting to blow up my gun or myself, so I’m going by the book (and thrilled with the results so far) but also a little confused about the contradictory info. I called Sierra and they didn’t have any explanation for the divergence. It seems like people here are blowing well past the highest book maxes I’m seeing, at least in Tikkas. Is this because Tikkas have higher than average pressure tolerances? Or are people relying more on observed pressure signs than published book maxes?

COAL.

Seating 77tmk bullet to meet standard 2.26 mag length, and Varget, lead to not a lot of room in case, and pressure, sooner.

Seating that bullet to a COAL of 2.4+” and you have a lot more room for powder, and it takes more powder to get to pressure.


If you’re going to use internet strangers’ data, and push limits, you need all of it - brand of brass, primers, bullet, COAL, CBTO, powder charge, velocity, possibly distance to lands.

None of these things matter if you follow book loads at standard mag length and start at minimums and work up.

Unless you have published failure analysis on action design, no brand “tolerates” pressure differently than any other. Not that you should trust anyway. Tikka isn’t special.

 

[rdp123]

Thanks! I was confused why I’m seeing divergence for similar weight bullets at mag length (2.26”). I guess maybe the tip leaves a little less space for longer COAL than a hollow point?

I follow book and got best accuracy at 21g and settled on that. I’m just trying to understand the info contradictory info seeing.

 

[KyleR1985]

Thanks! I was confused why I’m seeing divergence for similar weight bullets at mag length (2.26”). I guess maybe the tip leaves a little less space for longer COAL than a hollow point?

I follow book and got best accuracy at 21g and settled on that. I’m just trying to understand the info contradictory info seeing.

What contradictory information are you seeing?

 

[Axlrod]

Thanks! I was confused why I’m seeing divergence for similar weight bullets at mag length (2.26”). I guess maybe the tip leaves a little less space for longer COAL than a hollow point?

I follow book and got best accuracy at 21g and settled on that. I’m just trying to understand the info contradictory info seeing.

The differences you see are because they are all using different test barrels/chambers. And different brass and primers. This validates why you need to work up loads in your gun with your components. While working up you may find pressure before listed max loads or after. The most reliable indicator of pressure, is heavy bolt lift. This is where you need to decrease your powder charge.

 

[rdp123]

What contradictory information are you seeing?

The diverging max charges and people talking pretty commonly on here about exceeding them