Slug Velocity from a 12.5' barrel

[Clobbersauras]

good shooting! I guess deer at 75 yrds wouldn't be such a stretch...

I tried 50 yard and 100 yard with my Grizzly (first batch with light weight barrel) using red dot
I posted the result before but here they are for who didn't see them:

50 yard:

Typical 100 yard group:

Best 100 yard group:

Group always open up vertically. The reason is the 870's barrel is not free floating.

The Griz I used:

Now belongs to another GNZ

 

[Ike]

Interesting data Ike but I'm not sure that you can conclude from that, that there is a per inch loss of velocity, only that a 14" barrel shot slower than a 20" barrel. The majority of that velocity could have been lost between 14 and 15 or 16 inches. As shotgun powder burns so rapidly compared to rifle powders, the most dramatic losses of velocity are in shorter barrels and the per inch loss from 12-14 for example would be far more dramatic than from 18-22.

Sheephunter,
This wasn't intended to be a comprehensive study and no conclusions were drawn, only observation of different velocities of ammo through different barrels of different lengths including the shorter guns which were fairly new on the market at that point in time
The 8.5" was fired on a different day 500 km from the rest, I mixed three or four different shotguns as well including a Mossberg amongst the Remingtons. Slugs were not from the same lot and weather conditions were far different.

If I had taken several barrels then chopped and shot them from 20" to 8.5" under controlled conditions with repeated trials it would approach something that could be defensible but my 'tests' were just a fun day shooting a hundred or so slugs out of different guns.

Cheers

 

[sheephunter]

Oh for sure, I wasn't picking holes in what you did as it provides some interesting insight. I was just commenting on your comment.....

Velocity loss was 25-30 fps per inch of barrel lost.

 

[Ike]

No worries I didn't think you were

I didn't have the 8.5" results when I figured that number.
I see the actual 8.5" lost more which isn't surprising. I was surpised the 8.5" didn't lose more velocity given the ball of fire that came out the end.
Cheers

 

[Takujualuk]

I have been playing with my new Grizzly 12.5 with ghost ring sites and the replacable choke tubes. Just fantastic value. The functioning is flawless and on taking it apart to de-oil it the construction looks very rugged.

The 1 oz slugs from Win and Federal rated at 1600 get right around 1300. I get 2" groups at 25 yards. At 65 yards I am getting pretty ugly groups for a rifle shooter but they all go into the human torso targets at the range. Say 6-8" groups at 65 yards.

The 15, OO buck loads from Winchester go into 5 inches at 5 yards with 13 of 15 in 4" and 5 in the 1 inch aiming point. At 15 yards 11 of the 15 go into a 10" circle. By 25 yards the pattern is a bit thin. For bears I wouldn't use it past 5 yards or so and even then wonder about penetration.

Thinking of getting an invector choke in improved C and one in a rifled slug configuration. Needed to place the sight way off to the right to get it to hit to POI. It looks a bit funny but works just fine. 309.00! Fantastic deal!

On balance the 12.5 is plenty short and I wouldn't want to go shorter and lose even more ballistics. The 8.5 looks plenty mean though!