Groove and bore diameter of a 20 gauge rifled slug gun?

[eskimo36]

Does anyone here know the groove and bore diameter of a 20 gauge rifled slug gun from H&R?

[Scibaer]

well the figures i have say that the 20 gauge's bore diameter is .615 ( six hundred fifteen thousandths of an inch ) a full choke is .035 smaller and a modified is.020 smaller
 i dont see where they state the height of the rifling or the depths of the grooves.
maybe others here will have that info. but why would you be needing to know ? a special project ? please share
cheers, glenn

[eskimo36]

My plan is to shoot cast bullets out out of brass shotgun shells. I have found out today the groove diameter is .625 and twist is 1 in 28".  Big chumks of lead at 1000 fps is the direction I am headed.

[Scibaer]

ok so the rifling in the barrel is .010 of an inch high ? ..
 sounds like an intresting project.. have pics ? how long is the barrel going to be ? do you have a supplier for the brass ? casting your own slug im assuming ?
glenn

[eskimo36]

i haven't worked all through yet buy i have a receiver ready to go to H&R for a 20 guage slug barrel.  I have seen the brass on ebay in the past and cowboy action shooters use it on occasion.  I have not settled on a bullet yet and probably won't until i get the barrel and slug it.

[Scibaer]

well be sure to post any updates on your project , i'd be intrested in seeing the results
cheers, glenn