N120 in .20 practical, too fast?

[liasis33]

CZ, That's what I'm talking about. You've found that happy spot.

I wont settle for less. It's just a case of running out of components or money before I get there. :/

(the pic is 10 successive pills from my 6mm CM off a pair of bags @ 100... the 20p build is yet un-pillared, un-bedded and unfired)

I'm going to have to pull down one group, and was leaning heavier toward keeping the 40s... assuming they would handle SD winds a little better, if only a little. Considering your suggestion, and the terminal-end result of 32s vs 40s... is there a significant difference in destructive performance between the two?

RP

 

[TheCZKid]

CZ, That's what I'm talking about. You've found that happy spot.

I wont settle for less. It's just a case of running out of components or money before I get there. :/

(the pic is 10 successive pills from my 6mm CM off a pair of bags @ 100... the 20p build is yet un-pillared, un-bedded and unfired)

I'm going to have to pull down one group, and was leaning heavier toward keeping the 40s... assuming they would handle SD winds a little better, if only a little. Considering your suggestion, and the terminal-end result of 32s vs 40s... is there a significant difference in destructive performance between the two?

RP

The difference I don't know. The 40's would help against the wind, and I'm sure the PD's won't notice... at least only for a nanosecond!

I'd be glad to go out to SD and test the two loads, as it's on my short bucket-list to shoot PD's!

I'll look forward to hearing about the results. I purchases 2 pounds of 8208 from Brownells a few days ago, as they only had 1 pounders and a 2 bottle limit. Cost me about $107 for those 2 pounds, and it was the only time recently I found any in stock, so I bit the bullet and did it. $$$

 

[liasis33]

On my bucket list as well, lol.

New to SD in 2020 myself (voted with my feet) and finally made a social connection that led to an invite to an annual get together of folks. Itll be my first time. Started building the 20P pretty much immediately following the invite.

I am still figuring out the dos, dont's & hows of utilizing the public land. The state doesnt make it overly transparent despite alot of public land open to hunting.

Coyote calling is the next excuse for another smallbore rifle build.

 

[liasis33]

Finally... got to break in my 20P.

A big thanks to all who provided some load guidance & QL data, as 20P with N120 data is just non-existent.

As nervous as I was about the N120 being a fast / high pressure powder with a shallow case fill, it turned out to be the best performer of 4. The runner up was H335, which also had a shallow case fill. I was surprised to have the N133 outshined. IMR 4198 also got outpaced.

Data was produced with a Shilen 26" 1:10 twist. 32gr vmax, BR-4s & mixed brass. I averaged 10 shot strings expecting the mixed brass to affect the ES some. Outside temp = 77 degrees F.

19.5 gr = 3600 fps
20.0 gr = 3700 fps
20.4 gr = 3775 fps
20.8 gr = 3840 fps
21.0 gr = 3875 fps
21.2 gr = 3920 fps
21.4 gr = 3940 fps - primers start cratering
21.6 gr = 3950 fps
21.8 gr = 3940 fps? - significant craters
22.0 gr = 4005 fps - didnt go further.

H335 grouped awesome about 4000 - 4100 fps

 

[liasis33]

Finally found a happy spot for the 40gr vmax's. Trick seemed to be slowing them down to the 3500-3600 fps area. They really grouped in this speed with a variety of powders. Again, the N120 with its shallow case fill just excelled.

Also made it to the prairie. The folks that invited me to their honey-hole said theyve never seen it so populated in the 15 years they had been goin there. I'm ruined for life. Anybody considering a .20 cal for critter gettin... will not be disappointed.

Thanks everyone on the forum for the help.

 

[gunsandgunsmithing]

No reason to be scared of a little bit less than compressed, etc. N120 is awesome and worth testing further. Yes, it's faster that most but I'd use that powder in everything, if it would work. Maybe the best powder ever but limited in rifle use due to being relatively fast.