My .375 Cheytac velocitys with 24n41

[DillonT]

This is just a PSA incase it can help someone find a starting place with this powder. I went thru alot of components doing research since there wasn't much data I could find.

34" K&P barrel suppressed on DT HTI chassis using Peterson brass with 379 gr Berger solids.

Seen possible pressure signs at 146.6. Crunching powder when seating bullets around 140 grains.

124.5 2797
125.0 2813
125.5 2819
126.0 2834
126.5 2846
127.0 2868
127.5 2868*
128.0 2881
128.5 2889
129.0 2895
-
134.0 2938
134.2 2935
134.4 2966
134.6 2943
134.8 2932
135.0 2953
135.2 2968
135.4 2962
135.6 2962*
135.8 2972
-
137.0 2992
137.2 3028
137.4 3009
137.6 3012
137.8 3024
138.0 3038
138.2 3034
138.4 3029
138.6 3035
138.8 3047
139.0 3034
-
140.0 3059
140.2 3071
140.4 3079
140.6 3073
140.8 3065
141.0 3092
141.2 3108
141.4 3109
141.6 3102
141.8 3132
142.0 3105
-
145.6 3146
145.8 3175
146.0 3164
146.2 3173
146.4 3195
146.6 3197

 

[secondofangle2]

Wow man those are screaming velocities. I try to either that or 20 and 29. I forget which with the 390s. I sold it 2960 ft./s. If you’re pushing over 3100, that’s screaming. How is accuracy, by the way, I am shooting a 34 inch BART line with a suppressed DTHTI also

 

[232593]

OP How far off the lands were you running that 379 grain Berger?

Impressive numbers and results given the case volume of Peterson Brass.

 

[secondofangle2]

Any updates on this?

 

[DillonT]

Wow man those are screaming velocities. I try to either that or 20 and 29. I forget which with the 390s. I sold it 2960 ft./s. If you’re pushing over 3100, that’s screaming. How is accuracy, by the way, I am shooting a 34 inch BART line with a suppressed DTHTI also

Accuracy is fantastic! I shoot 2 mile stuff and got 9th place at Poke the Bear match out of 80 from all over the world. It was 2 years ago and my first match.

 

[DillonT]

OP How far off the lands were you running that 379 grain Berger?

Impressive numbers and results given the case volume of Peterson Brass.

I can’t remember exactly but beteeen 40 and 60 thousandths. I found solids like to have a jump

 

[232593]

This is just a PSA incase it can help someone find a starting place with this powder. I went thru alot of components doing research since there wasn't much data I could find.

34" K&P barrel suppressed on DT HTI chassis using Peterson brass with 379 gr Berger solids.

Seen possible pressure signs at 146.6. Crunching powder when seating bullets around 140 grains.

124.5 2797
125.0 2813
125.5 2819
126.0 2834
126.5 2846
127.0 2868
127.5 2868*
128.0 2881
128.5 2889
129.0 2895
-
134.0 2938
134.2 2935
134.4 2966
134.6 2943
134.8 2932
135.0 2953
135.2 2968
135.4 2962
135.6 2962*
135.8 2972
-
137.0 2992
137.2 3028
137.4 3009
137.6 3012
137.8 3024
138.0 3038
138.2 3034
138.4 3029
138.6 3035
138.8 3047
139.0 3034
-
140.0 3059
140.2 3071
140.4 3079
140.6 3073
140.8 3065
141.0 3092
141.2 3108
141.4 3109
141.6 3102
141.8 3132
142.0 3105
-
145.6 3146
145.8 3175
146.0 3164
146.2 3173
146.4 3195
146.6 3197

What was your barrel’s twist rate?

 

[secondofangle2]

What is COAL of this load?

Quickload is saying that, with case capacity 165 gr H20 and this bullet loaded to COAL 4.515", that the max is about 138.5 grains vv24n41, at 97% fill and a veolcity of 2897 fps from a 34" tube.

You are so far above that with your max loads in the OP, that I'd advise caution for anybody getting into compressed load territory with this particular recipe.

(QL says 100% capacity is at 143.0 grains; that gives 70541 PSI [max is 63817 PSI], and velocity 2988.)

I know QL is just a theoretical prediction, and I have a saying "never predict what you can simply observe".