20 Vartarg .150 Shorty.....

[ASbobcat]

Seems I'm again typing as you are.

Yes any other powders would be especially valuable to me. I have CFE BLK, Lil Gun, 2200, 2520, 1680, H110, if that's possible.

Wow I have to get GRT running. Sounds like it's an invaluable wildcat data source.

You have made my day....thank you.

My experience with 20VT can perhaps modify your list of potential powders. Using pistol/shotgun powders is tempting, because ballistics look impressive on paper, BUT there are serious downsides. These powders (H110 and Li'lGun) have wide swings in pressure with very small changes in charge. They also burn rapidly, dramatically increasing throat wear.

I would suggest H4198, RL-7, AA1680 and AA2200 for most consistent safe results.

 

[ricco1949]

My experience with 20VT can perhaps modify your list of potential powders. Using pistol/shotgun powders is tempting, because ballistics look impressive on paper, BUT there are serious downsides. These powders (H110 and Li'lGun) have wide swings in pressure with very small changes in charge. They also burn rapidly, dramatically increasing throat wear.

I would suggest H4198, RL-7, AA1680 and AA2200 for most consistent safe results.

10-4..I am aware of the temperaments of Lil Gun and H110 in K-Hornet.

I actually favor CFE BLK since I have all my VT experience with it and it has been easy to work with.

However the others may still apply, since .150 Shorty is on the edge of K- Hornet territory.

Thanks for the heads up.

 

[ricco1949]

Here's the lineup. FL VT, .100 Shorty and .150 Shorty

.150 Shorty's gonna be the first entry in the PD Sweepstakes.

Usable capacities of CFE BLK to the neck shoulder junction are as follows:

20.5 FL
18.5 .100 Shorty
17.2 .150 Shorty

 

[ASbobcat]

10-4..I am aware of the temperaments of Lil Gun and H110 in K-Hornet.

I actually favor CFE BLK since I have all my VT experience with it and it has been easy to work with.

However the others may still apply, since .150 Shorty is on the edge of K- Hornet territory.

Thanks for the heads up.

You're very welcome.

As a general rule, I use the slowest powder that will suit my needs.

Charge weight variations are less critical.
Less throat wear. Even though you're using more powder, more of the burn occurs beyond the throat.
Longer case life from lower peak pressure spikes.

 

[SmokinJoe]

Attached is a cartridge comparison , from left: K-Hornet, TCM, My 22 SmokiJoe, 22 Spitfire, 22 Tanuki and 221 FB. I have tried 300MP, AA1680, CFE BLK, Shooters World Black and Shooters World SBR-SOCOM. The SBR-SOCOM has turned out to be the perfect powder for both the Spitfire and SmokinJoe with 40gr bullets. 300MP would be my second best. looks like your cartridge will be very similar to mine other than being 20cal vs 22. Best thing about wildcating a cartridge based on 223 is brass.

 

[ricco1949]

Ran into a problem....

My Giraud trim die is made with my 20 VT reamer. The prototype type Shorty brass I've made won't fit in the die all the way. First thought was the neck is snug because of the thicker necks on Shorty. Nope I'd already reamed it bigger years ago to avoid this scenario.

Got out the 17 Fireball SAAMI drawing and my 20 VT drawing. Ohhhhh.... I overlooked that the 17 Fireball is .005 bigger at the shoulder than the 221 FB and the 20 VT.

My 20 VT reamer ain't gonna be compatible with my 17 FB die converted to 20 VT.

Back to the beginning...order another die to cut off.... 20 VT this time.

 

[20 TAC]

Ran into a problem....

My Giraud trim die is made with my 20 VT reamer. The prototype type Shorty brass I've made won't fit in the die all the way. First thought was the neck is snug because of the thicker necks on Shorty. Nope I'd already reamed it bigger years ago to avoid this scenario.

Got out the 17 Fireball SAAMI drawing and my 20 VT drawing. Ohhhhh.... I overlooked that the 17 Fireball is .005 bigger at the shoulder than the 221 FB and the 20 VT.

My 20 VT reamer ain't gonna be compatible with my 17 FB die converted to 20 VT.

Back to the beginning...order another die to cut off.... 20 VT this time.

I’ve often asked myself about these projects I’ve taken on….is this a Labor of Love or a Love of Labor? . Hang in there lol

 

[ASbobcat]

Ran into a problem....

My Giraud trim die is made with my 20 VT reamer. The prototype type Shorty brass I've made won't fit in the die all the way. First thought was the neck is snug because of the thicker necks on Shorty. Nope I'd already reamed it bigger years ago to avoid this scenario.

Got out the 17 Fireball SAAMI drawing and my 20 VT drawing. Ohhhhh.... I overlooked that the 17 Fireball is .005 bigger at the shoulder than the 221 FB and the 20 VT.

My 20 VT reamer ain't gonna be compatible with my 17 FB die converted to 20 VT.

Back to the beginning...order another die to cut off.... 20 VT this time.

Interesting information. I was unaware of the difference in shoulders. .005 is significant.

 

[ASbobcat]

Attached is a cartridge comparison , from left: K-Hornet, TCM, My 22 SmokiJoe, 22 Spitfire, 22 Tanuki and 221 FB. I have tried 300MP, AA1680, CFE BLK, Shooters World Black and Shooters World SBR-SOCOM. The SBR-SOCOM has turned out to be the perfect powder for both the Spitfire and SmokinJoe with 40gr bullets. 300MP would be my second best. looks like your cartridge will be very similar to mine other than being 20cal vs 22. Best thing about wildcating a cartridge based on 223 is brass.

I agree about the quality of 223 brass, particularly LC NATO.

I love the efficiency of these small cases. My observations from decades of playing around with various cartridges is that there is an "optimum" case capacity for any given bore diameter (powder burned vs velocity). I suggest that the VT is optimum for 20cal, but the smaller variants are probably better suited to .17cal.

 

[ricco1949]

Well guys after nearly two years the 20 VT .150 Shorty is finally born, alive and well.



Here's my original load work up with 1680 in 26" X-Caliber 1.250 straight.



Thank you @Evan... your GRT load workup was invaluable. I still loaded first round at +/- minus 10% or 14.0 grains, covered with rubber mat and rug for first firing, and used pull cord from behind barrier. Can't to too safe.

@Gabe22BR.... you were pretty much spot on with your 16g prediction to achieve 3600 and 32 VM. I was hoping 15g might get there.

Shorty ain't done yet I just had to do this trial load run to see if the cartridge is viable....it's GTG.

Will continue this with more detail later on the build but this was just to let the shooting world know that Shorty lives.

 

[alf]

Good stuff Ricco!

 

[ggshoots]

Hi Rick, glad to see you are back at this.

My case is very similar with length dimension almost the same as the 22 Spitfire. I have blown out shoulder and 40deg. I now only use 300BO cases to form brass. Since it is only slightly longer the neck thickness is close enough that I don't need to turn. I do have a list of brass that works well as some that don't. Some is so hard it is a pain to work with.

With my case using 14gr N110 and 40gr Vmax I get 3325fps. and very accurate. I have pushed this up over 3500. I think you should have great brass life as well as barrel life. I know I got over 12 firings before I ever trimmed and no brass failures. I did also go to Starline 300BO brass for new brass. I haven't tried the 1680 powder, may have to look at this but N110 has worked awesome.

I would like to do this in a 20 like yours but I have 3 Mauser actions I am working with building rifles for my son and I. The case will take 15gr of powder so with a 32gr bullet should easily get up in the 3600-3800fps range. May be a while. Lol

Just curious as to 32 vs heavier bullet weight in your Shorty. Is the loss of velocity vs heavy weight worth it to get less drift at longer ranges in the wind? I've never shot 20's so have no clue.

Keep at it, I will give you a call sometime.

Glenn