88 TMK Loading Thread

[NWBLKTAIL]

8 twist, 20" 223 for the 77 tmk.

7 twist, 16.5" 22 creedmoor for the 88.


I also tested nas3 cases in the 8 twist , 20" 223 for accuracy and velocity.
I used Varget powder with the 88 tmk seated to 2.45 COAL.

Velocities ranged from 2750 to 2900 fps in my ladder. The 8 shot ladder produced a .850 inch group at 100 yards. The 2900 fps charge showed primer catering. This was with Winchester #41 primers. Probably unsafe, so I won't load that hot again. Im hesitant to share my powder charges, because this is uncharted territory and Probably stupid.


I am going to test the 88s out of the 8 twist 223 at distance to see if they remain stable.

I’ve used varget quite a bit in 223 I feel like I have an idea where you ended up to get that speed.

Nice waiting for my box of 100 88’s to show up see if I can stabilize them in 8tw 22-250 at sea level

 

[B_Reynolds_AK]

A lot of guys are concerned about stability in 1:8 twist barrels, from 223 to 22 CM.
I’ll go out on a limb and say that it’s worth building a gun around the 88 TMK.

Whether this is a 1:7 223 with a long throat or any of the bigger cartridges.

The PVA barrel I have on my 223 was an inspired decision it seems.

TLDR: If it doesn’t stabilize, get a barrel that will, because I predict we’re going to see a lot of animals put down with it this coming year.

 

[nm.otter]

I’ll go out on a limb and say that it’s worth building a gun around the 88 TMK.

It's tempting me to pivot from a 6mm GT to a .22 ARC.

Neither would suck, but a .22 ARC could work in a Sako XS action...

 

[Jgormond3]

For what it's worth, I tested the 88 tmk vs the 77 tmk in one gallon water (previously milk) jugs. The jugs were standing upright (caps up).

Both bullets were doing right around 2750 fps at the muzzle. Jugs were at 50 yards.
The 88 penetrated into the 3 jug and was found inside it. The 77 exited the 2nd jug and bounced off the 3rd and was found on the ground.

Of course water isn't the same as animal flesh; it is very hard on bullets. But I have found it to be a consistent test medium to just catch bullets in. I have shot a lot of jugs with the 77 tmk, and I have never had one make it into the 3rd jug.

So I expect that the 88 will have more exits on deer sized animals than the 77, which if it does, will make woods Whitetail hunters happy.

Im looking forward to this fall's hunting reports...

I hope shortly we can get some depreciation tag and or hog results. I’m crossing my fingers this 88TMK pans out as a bad little whitetail bullet or else I’ll have to buy a thermal and make this rifle a coyote rig.

 

[doverpack12]

I just got my ULUL 22 ARC straight pull load figured out with 75 ELDMs.

With my data and environmentals I would need 2750 fps with the 88 TMK to match 75 ELDM 1800 fps threshold. Not sure I can get there, factory 88 ELDM were 2560 fps. I’m currently loading 2860 fps which is about 100 fps faster than factory 75 ELDM.

I’m currently using Hornady brass because I have 400 ish pieces. Is there a meaningful gain in velocity potential moving to Alpha brass in a non bolt action rifle?

 

[AM_Hunter]

I have run some .308 NAS cases through my Redding body die using imperial wax. I also ran them through my Redding neck bushing die and put a TiN coated expander mandrel through them.

I can’t say if it was successful or not because I still have stiff bolt close after resizing. That may just be the nature of the alloy cases.

But I did manage to fire and reload a single case 3 times. I pushed a 168 grain ABLR at 3060 fps in a 20” Tikka .308. I used CCI34 primers and no pierced primers.

I want to try some 223 cases but I don’t want to buy 250 of them. If anyone is interested in splitting an order, let me know.

What powder were you using? I got a pressure test for 44.5-49gr of Varget for a 168TTSX ready to go with the NAS3 cases and could tell 48.5 and 49 were compressed. Im expecting the 49gr mark to hit around less than 2900fps so I'm curios what youre doing to push over 3000.

Also are you neck sizing at all before you load these cases? I didn't feel like I was getting consistent seating. I did chamfer and deburr but even that didn't feel super effective, I wonder if its because the case is stronger than my chamfer/deburr bits?

 

[nm.otter]

I just got my ULUL 22 ARC straight pull load figured out with 75 ELDMs.

Can that straight pull handle bolt gun chamber pressure, or does it have to shoot gas gun loads?

 

[doverpack12]

Can that straight pull handle bolt gun chamber pressure, or does it have to shoot gas gun loads?

I’m using gas gun data as my start point and generally find pressure just above book for Hornady and Sierra data.

 

[SouthPaw]

I've occasionally thought about getting a 7tw barrel with the longer throat for my 223. It would lighten the gun a bit since the CTR barrel is a bit porky. The 88tmk is probably gonna push me over the edge. Can't shoot suppressed here, so likely a 22 or 24 inch barrel. That should get the 88s scooting decently.

 

[Thegman]

Far from definitive, but all I had time for.

This was 5 shots @ 100 yards from my T3 Superlite 1 in 8 twist. First (and only) load I tried with the 88s, but it looks like 1 in 8 might stabilize the 88 TMK (??)

 

[B_Reynolds_AK]

Far from definitive, but all I had time for.

This was 5 shots @ 100 yards from my T3 Superlite 1 in 8 twist. First (and only) load I tried with the 88s, but it looks like 1 in 8 might stabilize the 88 TMK (??)
View attachment 1041933

It's out at 500 and beyond that you'll really be able to tell. If your hits starting dropping low and you have to input a lower BC to line up, you'll know they are marginally stable. That's what I found with a factory 8 twist 223 and 80's atleast. Can you shoot across the Mat river close to home out there?

 

[Thegman]

It's out at 500 and beyond that you'll really be able to tell. If your hits starting dropping low and you have to input a lower BC to line up, you'll know they are marginally stable. That's what I found with a factory 8 twist 223 and 80's atleast. Can you shoot across the Mat river close to home out there?

Did you just get a lower BC value and more drop than expected, or did accuracy fall apart out there too?

I don't often shoot stuff that far out, but that lower BC would also be lower effective range for the bullet to perform well, which could be pretty important.

Yes, if I turn the rifle 90 degrees, I'm shooting across the river.

To add: I hadn't planned on doing a ton with these bullets in this rifle, but if they shoot well, maybe. When I get a chance, I'll shoot some and check velocities with the Lab Radar as well. If bullets are really unstable, I can sometimes see the BC dropping off down range within 100 yards.

 

[B_Reynolds_AK]

Did you just get a lower BC value and more drop than expected, or did accuracy fall apart out there too?

I don't often shoot stuff that far out, but that lower BC would also be lower effective range for the bullet to perform well, which could be pretty important.

Yes, if I turn the rifle 90 degrees, I'm shooting across the river.

To add: I hadn't planned on doing a ton with these bullets in this rifle, but if they shoot well, maybe. When I get a chance, I'll shoot some and check velocities with the Lab Radar as well. If bullets are really unstable, I can sometimes see the BC dropping off down range within 100 yards.

Accuracy was still good, but I saw a significant drop off in point of impact. That wasn’t the case anymore once I put on a 1:7 twist bbl.