Mossberg 151MB odd rifling

[uhjohnson]

Just received the Mossberg
151MB I won in an auction and noticed the lands have a concave curve and the grooves extend out past the muzzle a few thousands. When viewed straight on it looks like an eight pointed circle. Does anyone have a Mossberg with rifling like this and if so how accurate is it. It doesn't appear any of the grove extensions are folded inward towards the bore

[northmn]

Most of the old Mosbergs I have seen shoot very well. All I can say is to shoot it and see.

DEP

[243winxb]

Does not look normal to me. I would ask here in the Mossberg fourm. https://www.rimfirecentral.com/forums/index.php

My muzzle.

[Shepherd2]

The crown on my 151M(a) looks identical to the muzzle on 243winxp's rifle and on several other vintage Mossbergs that I have. The rifling on the 151 has sharp corners as do all my Mossberg .22s. Is your rifle's barrel orginal?

[ulav8r]

Looks like a replacement barrel that waas button rifled and not crowned afterwards. I have three Green Mountain barrel blanks where the grooves are extended like that.

[uhjohnson]

It appears original, however i do not know who owned it prior to me. Could this be a reject barrel that was put on a receiver or an experimental barrel with a crown not finished

[243winxb]

https://www.rimfirecentral.com/forums/showthread.php?t=541190
AC KRO GRUV is Mossberg version of marlins Microgroove .

Would seem to be normal, but limited type of rifling?

Google
AC KRO GRUV