Sierra 88 TMK Load Data

[Gstew1930]

Hornady 6.5 CM Match turned into 22 Creed. I put One Shot on the case body and powder graphite on the neck and crank em out and then trim. I trim them again after fire forming and that's it.

I should reorganize that list above for public posting:


Near Pressure Loads:

39 gr H4350 is 3025FPS, too hot, go 38.5gr

40.8gr Staball 6.5 is 3050 fps

H4381SC max loads are going to be around 42.5gr (2750 fps in 14.5" barrel)


Quick Drop Loads: (you can't get pressure with these powders)

44gr H1000 is 2775 fps

45.5gr Staball HD is 2775fps (46.3gr Staball HD is 2850fps…full…like stuffed)

Verify 44gr N565 is 2900fps. Is 42.5gr 2775fps? (44gr is STUFFED)


I cut one 18" barrel down to 14.5" given my speed goals and I'm sending the other one to get cut so it will be ready to go when the barrel I'm shooting is worn out. H4831SC is my jam right now. Delightful accuracy.

I gotcha. Ive only used alpha so the case capacities are a little different

 

[SloppyJ]

I gotcha. Ive only used alpha so the case capacities are a little different

What were you seeing Garrett? I have the same alpha srp. Imagine the capacity is a bit lower?

Had a trusted source share his load data of 43gr+ N555 shooting absolutely amazing. Seems hot to me but he has multiple firings on it.

 

[Gstew1930]

What were you seeing Garrett? I have the same alpha srp. Imagine the capacity is a bit lower?

Had a trusted source share his load data of 43gr+ N555 shooting absolutely amazing. Seems hot to me but he has multiple firings on it.

Yeah case capacity is a bit lower but the brass is pretty damn tough. I always lean on it anyways. I have not tried N555. I'd take it down 2 grains & work up

 

[Hill Difficulty]

Finished my 223 Rem load dev at 24.5 grains of H4895. Shot 6 rounds tonight with ave FPS @ 2,773. Pleased with the accuracy and velocity, easy loading.

***EDIT to note that the charges I'm listing appear to be overpressure.***

 

[sierracharlie338]

Finished my 223 Rem load dev at 24.5 grains of H4895. Shot 6 rounds tonight with ave FPS @ 2,773. Pleased with the accuracy and velocity, easy loading.

That a standard 223 chamber or something special?

 

[Hill Difficulty]

Chamber is 223 Rem Match, just longer freebore. Barrel is a Criterion prefit.

 

[SloppyJ]

Chamber is 223 Rem Match, just longer freebore. Barrel is a Criterion prefit.

How long is it? I push 75 bthps around that same velocity with a case full of varget in mine and I have a longer freebore as well. You have those 88s smoking!

 

[Hill Difficulty]

How long is it? I push 75 bthps around that same velocity with a case full of varget in mine and I have a longer freebore as well. You have those 88s smoking!

For the TMK 88s the BTO is 1.99" and currently seating at 2.52" OAL. Could seat a little longer but run out of max mag length @ 2.55 inches. Need a little space for tip nose clearance.

Note that the POI is the same from 23.5 to 24.5, 2.48" to 2.52" OAL seating. Bullet not fussy at all.

***EDIT to note that the charges I'm reporting are overpressure.***

 

[Castle Rock]

Finished my 223 Rem load dev at 24.5 grains of H4895. Shot 6 rounds tonight with ave FPS @ 2,773. Pleased with the accuracy and velocity, easy loading.

View attachment 1055603

New brass?
That’s a really hot load.

 

[sierracharlie338]

For the TMK 88s the BTO is 1.99" and currently seating at 2.52" OAL. Could seat a little longer but run out of max mag length @ 2.55 inches. Need a little space for tip nose clearance.

Note that the POI is the same from 23.5 to 24.5, 2.48" to 2.52" OAL seating. Bullet not fussy at all.

Any idea on actual freebore .069 or .100?

 

[SloppyJ]

For the TMK 88s the BTO is 1.99" and currently seating at 2.52" OAL. Could seat a little longer but run out of max mag length @ 2.55 inches. Need a little space for tip nose clearance.

Note that the POI is the same from 23.5 to 24.5, 2.48" to 2.52" OAL seating. Bullet not fussy at all.

I was talking barrel length

 

[Schmo]

Not bad for 10 shots from 2 different shooters…

 

[Schmo]

And this isn’t terrible for 10 shots either. Not sure if the stray shot is me or the load, but the measurement includes it. I’ll reshoot that load again tomorrow and see what happens.

 

[Hill Difficulty]

SloppyJ - Barrel is 17"

SC338 - Freebore is .090"

Castle Rock - Brass is unfired Lapua Match headstamp

CORRECTION: Am going to mark my recent posts to note that the charges I've been using appear to be overpressure.