Sierra 88 TMK Load Data

[43.6N]

Do we have a consensus G1 BC for the 88tmk? I was seeing some chatter that the published number is off?

I can’t speak for anyone else. But on my rig, the 0.263 g7 bc has held up out to 1120yds.

I’ve also figured out a solution for 5 round 223 aics mags that I’m happy with. But that’s for another post lol.

18” 223
23.0gr 8208xbr
2690fps
Swfa 3-9
Rokstok

 

[jonnyviceroy]

22 Creed
@hereinaz ls wild 18” PBB .120 fb
88 tmk
43.7 h1000
Alpha brass
Cci 450
2.745 coal
2985 fps

Still in the first 50 rounds, no signs of pressure & hoping it still speeds up a bit. These are just 5 shot groups but so far each one of them looks about the same as these.

 

[B_Reynolds_AK]

Do we have a consensus G1 BC for the 88tmk? I was seeing some chatter that the published number is off?

G1 .52 for me @ 2700 fps.

 

[mtnbound]

Do we have a consensus G1 BC for the 88tmk? I was seeing some chatter that the published number is off?

G1 .525 is what I use.

 

[Dude270]

My dope has lined up with the .525 G1 BC.

 

[Hill Difficulty]

~68% more powder just to get 200 more FPS?

.22 ARC is looking better and better here...

Am liking the ARC, too. My new take with the 88 is 22 ARC wins if a barrel is 16 to 20 inches, 22 CM if 20" or over.

With my criteria being limited to the combination of chambering/bullet seating, case volume limits, performance, and production magazine lengths, the 88 TMK appears to match up best with the 22 ARC.

Just seems the 22 ARC offers the best combination of performance and loading flexibility (lack of limitations).

Pic shows 223 Rem w/88 seating @ 2.53" OAL. That's about max length I can go with a 2.55" magazine and .090" freebore/throat. Even when maxing mag length, note 25% of the bullet length beneath the top of the shoulder.


See crude pic of the same 223 Rem round next to ARC brass. With production magazines at 2.48 inches, appears the 88 can seat with bottom of bullet shank at middle of neck and still have a little mag clearance, allowing case volume to be maxed out.


ARC (vs 223 Rem) advantages are 1) can seat 88 wherever you want to max case volume and not exceed production mag length, 2) ARC has greater fps w/35 grains of capacity vs 223 Rem @ 30 (comparing fired case volume). Keep in mind the 223 Rem case area used up by bullet base, compressing powder, etc.

Looking forward to seeing 88 results for longer-throated 22 ARC bolt guns.

 

[Stumpy208]

22 ARC
16.25"
1/7.5"

Starline virgin brass
Federal 205
28gr of Varget
2.300" COAL

2711fps average
20fps es
6.2fps std

I had one round that had a little heavy bolt lift and an ejector mark, but the other 9 were fine.

Including the heavy bolt lift flyer the group was 1.91".


Without the flyer the group was 1.12".

 

[Dude270]

I had to back my 22 ARC load down a grain after shooting in some higher temps.

Originally, 29.0 gr of Lever gave me 2830 fps (factory 22" howa) with 2 light ejector marks out of 10. Groups were good.

I tried that load again on a day temps were in the mid 80s. Ammo and rifle were in the truck in the sun, so it was pretty warm. Serious ejector marks on all fired.

I backed down to 28.0 grains and no more pressure signs. Accuracy was about the same and speed dropped to 2730 fps.


For reference, my 20" 22 creedmoor is moving them at just under 3100 fps with 12 more grains of powder.

 

[Lawnboi]

I can’t speak for anyone else. But on my rig, the 0.263 g7 bc has held up out to 1120yds.
View attachment 1071267
I’ve also figured out a solution for 5 round 223 aics mags that I’m happy with. But that’s for another post lol.

18” 223
23.0gr 8208xbr
2690fps
Swfa 3-9
Rokstok

What bottom metal?

 

[BLJ]

What bottom metal?

Looks like a Redsnake Hunter.
My guess.

 

[43.6N]

Looks like a Redsnake Hunter.
My guess.

That’s the one

 

[Lawnboi]

That’s the one

In a ctr Inlet?

 

[43.6N]

In a ctr Inlet?

That Rokstok was a standard tikka inlet.
Required a little dremel work to get it to fit.
I have a fairly detailed post on the fitting procedure I’ll try and link to for you.

 

[43.6N]

In a ctr Inlet?

Post in thread 'RokStok'
https://rokslide.com/forums/threads/rokstok.329754/post-4644338

Pictures start a few posts later

 

[BLJ]

That’s the one

Is that a 5 round mag?

 

[43.6N]

Is that a 5 round mag?

Yessir.
5 round steel 223 accurate mag.
I opened up the polymer spacer to accommodate 2.55” OAL

 

[WDR]

I was able to get to 2500fps in my 20" 7 twist Savage loading to ~2.40"ish OAL (about the max my factory mags can take, but also about the max the throat allows) and using N540... No pressure signs yet. I didn't have solid load data, so I started at 20grs and worked up from there to 22gr. Nothing amazing group wise (MOAish), but it was windy as hell, and I was really just testing for pressure and velocity. I think I still have some room to go up.

If I can get to 2600ish out of them, the juice might be worth the squeeze. Probably a bit too much bullet for my rifle unless I get it throated. The good news is the 77TMK shoots at least as well as the 80gr ELDs I used to kill a deer and a cow elk last year, so I could always just go back to the slightly lighter bullets. I did shoot a 5rd group with the 77TMK that had all the rounds touching.

 

[Tullis94]

Tikka 22 creed with a 20" PBB.
39 grains of H4350. ( Hot load)
3162 FPS
Alpha srp brass
I dont know the COAL. I roughly found the lands and then seated about 30 thou deeper.

I currently shoot 80 eldms which have shot slightly better than this, but not enough to matter. Im going to try 38.5 grains of powder and then compare the ballistics between the 2. I have about 250 shots on this barrel and enough 80s to finish it off so im not sure I'll make the switch. I am happy with how the 88 TMKs shot though!

 

[rafiki]

22CM 16.25” PBB .120 FB

About 65 rnds total thru the barrel so far
No pressure signs. Might try to squeeze some more speed out of it but this would be totally adequate as is.

 

[Grizzle]

22CM 16.25” PBB .120 FB

About 65 rnds total thru the barrel so far
No pressure signs. Might try to squeeze some more speed out of it but this would be totally adequate as is.

I've gotten better speed with h4350 than I have h4831sc or h1000 if you are looking to pick some up. I'm right around 3100 with a 20" and same freebore