Results: Cutting a 7mm-08 Barrel From 26" to 20"

[tylsmith33]

In my opinion, there's not enough threads with data from cutting down barrels!

I cut down my 26" 7mm-08 barrel to 20". I tested 7 loads before and after and wanted to share the data. Bullets and powders were picked based on what I have on hand. ***Disclaimer, all loads were max in my rifle and should not be attempted***

Why 20"? I figured it would be a good balance between too long to hunt with the can and too short to be tolerable from a noise perspective.

	Speer 130gr	50.2g H4350	Lost	Speer 145	48.0g H4350	Lost	Interlock 139	48.0g H4350	Lost	162 ELD-M	45.0g H4350	Lost	150 SPFB	45.9g IMR4451	Lost	162 ELD-M	45.1g IMR4451	Lost	162 ELD-M	46.0g IMR4831	Lost
	26"	20"		26"	20"		26"	20"		26"	20"		26"	20"		26"	20"		26"	20"
1	3126	2993		2986	2865		2972	2855		2730	2649		2765	2705		2710	2622		2660	2587
2	3108	2995		2980	2870		2974	2847		2717	2653		2820	2677		2688	2610		2660	2595
3	3126	2990		2980	2871		2982	2858		2723	2658		2772	2684		2731	2594		2648	2584
AVG	3120	2993	127	2982	2869	113	2976	2853	123	2723	2653	70	2786	2689	97	2710	2609	101	2656	2589	67
SD	10	3		3	3		5	6		7	5		30	15		22	14		7	6
ES	18	5		6	6		10	11		13	9		55	28		43	28		12	11

Average Lost: 100 FPS
Average per Inch: 16.63 FPS

Sadly my rifle prefers much lower charge weights than the max, but the FPS lost per inch was less than I expected. The difference in velocity won't be missed as the rifle is much more enjoyable to shoot with a silencer on it now and the speeds are still quite good. In many cases the choice in powder will have a larger impact on the velocity than having cut down the barrel. I still need to pick up some of the more traditional 7mm-08 powders to try, once supply improves.

Did you do this test suppressed or not?

 

[Another Casual]

Did you do this test suppressed or not?

Numbers are both without suppressor. My Magneto speed sporter doesn't play well with a can.

 

[Another Casual]

What's equally interesting is your ES/SD improved or stayed equal.
Head scratcher!

Sample size of 3! Wouldn't read too much into the ES/SD numbers.

 

[Bob Wright]

Sample size of 3! Wouldn't read too much into the ES/SD numbers.

Not the SD so much. It needs way more data, agreed.

 

[John Klingenberg]

In my humble experience, if the data is consistent, even in small samples it will carry through. As long as the range data holds with the paper data just shoot it as it stands. I was obsessed with tiny groups before I shot my first PRS style match. Then I realized that a 3/4 MOA rifle was perfectly competitive. Same for game animals. The target is big enough to be hit.

 

[Stewart2550]

I cut my 300 PRC barrel from 26" to 20", shot the same load I was shooting through it. Lost 188 fps and my SD went from 12 to 7. I didnt do too much testing but I had some ammo left over so I shot it to compare.

 

[sierracharlie338]

Outstanding work sir! Thanks for sharing