My bullet lube test results

[Spencercoc74]

I have big velocity variances, well they started out big. I did my research, got a new 0.338 bushing, and went testing yesterday. The original 20 rounds got bumped to 35. The 5 round groups were a last minute addition. Adding dry lube (Imperial) to the bullet and inside of the neck does not appear to be effective. Hopefully brushing the inside of the neck is my solution but needs to be tested again with a larger sample size.

Rifle
Projectile weight	168.0 gr
Average velocity	2591.5 FPS
Minimum velocity	2582.3 FPS
Maximum velocity	2605.6 FPS
Standard deviation	7.9 FPS
Extreme spread	23.3 FPS
Average power factor	435.4 KGR-FT/S
Average kinetic energy	2504.9 FT-LBS
Session notes	N540 43.7 338 neck 2.797
SHOT #	SPEED (FPS)	DEV/AVG (FPS)	KE (FT-LBS)	POWER FACTOR
1	2595.1	3.6	2511.9	436.0
2	2582.3	-9.2	2487.2	433.8
3	2593.8	2.3	2509.3	435.8
4	2597.4	5.9	2516.3	436.4
5	2583.3	-8.2	2489.1	434.0
6	2605.6	14.1	2532.2	437.7
7	2587.6	-3.9	2497.3	434.7
8	2585.3	-6.2	2492.9	434.3
9	2583.7	-7.8	2489.7	434.1
10	2600.7	9.2	2522.7	436.9
Rifle
Projectile weight	168.0 gr
Average velocity	2604.9 FPS
Minimum velocity	2586.6 FPS
Maximum velocity	2621.4 FPS
Standard deviation	10.8 FPS
Extreme spread	34.8 FPS
Average power factor	437.6 KGR-FT/S
Average kinetic energy	2530.9 FT-LBS
Session notes	N540 43.7 338 neck 2.797 Dipped bullet
SHOT #	SPEED (FPS)	DEV/AVG (FPS)	KE (FT-LBS)	POWER FACTOR
1	2621.4	16.5	2562.9	440.4
2	2586.6	-18.3	2495.4	434.6
3	2610.6	5.6	2541.8	438.6
4	2601.4	-3.5	2524.0	437.0
5	2603.3	-1.6	2527.8	437.4
6	2591.5	-13.4	2504.9	435.4
7	2597.8	-7.2	2517.0	436.4
8	2605.0	0.1	2531.0	437.6
9	2612.2	7.3	2545.0	438.9
10	2619.4	14.5	2559.1	440.1
Rifle
Projectile weight	168.0 gr
Average velocity	2615.2 FPS
Minimum velocity	2609.9 FPS
Maximum velocity	2620.1 FPS
Standard deviation	3.9 FPS
Extreme spread	10.2 FPS
Average power factor	439.4 KGR-FT/S
Average kinetic energy	2550.9 FT-LBS
Session notes	N540 43.7 338 neck 2.797 Brushed neck
SHOT #	SPEED (FPS)	DEV/AVG (FPS)	KE (FT-LBS)	POWER FACTOR
1	2609.9	-5.3	2540.5	438.5
2	2618.4	3.2	2557.2	439.9
3	2616.8	1.6	2554.0	439.6
4	2610.9	-4.3	2542.5	438.6
5	2620.1	4.9	2560.4	440.2
Rifle
Projectile weight	168.0 gr
Average velocity	2600.5 FPS
Minimum velocity	2584.6 FPS
Maximum velocity	2609.6 FPS
Standard deviation	8.5 FPS
Extreme spread	24.9 FPS
Average power factor	436.9 KGR-FT/S
Average kinetic energy	2522.3 FT-LBS
Session notes	N540 43.7 338 neck 2.797 Q-tip dry lube
SHOT #	SPEED (FPS)	DEV/AVG (FPS)	KE (FT-LBS)	POWER FACTOR
1	2609.6	9.1	2539.9	438.4
2	2584.6	-15.9	2491.6	434.2
3	2602.7	2.2	2526.5	437.3
4	2604.3	3.8	2529.7	437.5
5	2601.4	0.9	2524.0	437.0
Rifle
Projectile weight	168.0 gr
Average velocity	2617.7 FPS
Minimum velocity	2600.4 FPS
Maximum velocity	2642.7 FPS
Standard deviation	14.8 FPS
Extreme spread	42.3 FPS
Average power factor	439.8 KGR-FT/S
Average kinetic energy	2555.8 FT-LBS
Session notes	N540 43.7 338 neck 2.797 Dipped case
SHOT #	SPEED (FPS)	DEV/AVG (FPS)	KE (FT-LBS)	POWER FACTOR
1	2642.7	25.0	2604.8	444.0
2	2600.4	-17.3	2522.1	436.9
3	2625.7	7.9	2571.3	441.1
4	2608.9	-8.8	2538.6	438.3
5	2610.9	-6.8	2542.5	438.6

 

[R_A_W]

Hopefully brushing the inside of the neck is my solution but needs to be tested again with a larger sample size.

What brass, how many firings, what & how are you cleaning brass, what’s your brass prep?

I’ve seen residue form inside of necks after tumbling with a polishing agent, which caused inconsistent & increased seating force. Came to mind immediately since brushing necks producing the lowest SDs

 

[ShtrRdy]

Would you mind summarizing the data to what method was used and the average, SD, and ES numbers?

 

[Spencercoc74]

More details: Lapua brass. This is the third firing. I did anneal and full length size (without the neck bushing) after the second firing. Ultrasonic cleaned with green RCBS case cleaner then tumbled with walnut shells to dry. chamfered and deburred. I am neck sizing as needed instead of in a batch. No polishing agent was used, but you have me thinking it may be time to change the media.

I used no magic to compile the data. the output you see is the output from the Athlon Rangecraft Chrono. each group was a separate session then I pasted the pertinent data into a singe spreadsheet so it's easier to review and compare. The session notes were added through the Athlon app.

 

[patriotnation]

If you only brushed inside the necks on only one of your groups and you annealed them all, that would make a difference I think.

If you anneal, then you should brush