.678 & .735 rb

Loading these two rounds for my Mossberg 500.

Legitimately what should I expect from this gun:

rifled barrel with open sights.
52 year old eyes.


I haven't shot open sights on a long gun since,... The time I could afford a scope.


Scott

I don't think you will do much worse than a 3" group at 50 yards. I've easily got 2.5" groups with a rifle barrel open sight gun, and that's the one and only load I ever tried with the .735" round ball. Even the smooth bore puts them inside of 4".

Though you might not believe me from my latest posts... my experience with round balls in smootbore is very good. Of course it takes good loads as well.

My best results so far are with 0.662" RB's patched to snug fit in a wad/barrel ~ they get loaded into hulls with shotcups much as you would patch a round ball into a muzzleloader. I was getting consistent 3" to 4" groups at 50 yards with those from a single shot Cooey 12 ga. smoothbore (cylinder bore) with rifle sites added.

The trick there was proper patching and using a 16 or 20 ga. 1/8" nitro card wad in the bottom of the shotcup then a small scoop of Cream 'O Wheat, then the snuggly patched RB.

Just as successful was the 0.735" RB. This one I found worked best for me over a hard card wad column with plastic gas seal over the powder. Again, groups ran 3" to 4" at 50 yards. This one you want to be sure is only shot through cylinder bore guns! I have not tried through a choke and do not want to!

I also have a 0.678" RB mould and it is a good fit in several standard shotcups though I have not found quite as good accuracy yet.

A benefit of the 0.662" and 0.678" RB's is that they are a "standard" slug weight so lots of load data can be used. The 0.735" RB weighs about 1 3/8 oz. so is heavy. I used a load for Precision Rifle's 610 gr. Piledriver full bore slug using Blue Dot. That worked well for me. Load data for heavy slugs is scarce though you can use birdshot load data for equal weight payload

I got some limited shooting in using a borrowed rifled Remington 870 and those same 0.725" RB loads groups around 2" at 50 yards and likely they could have done better but the shooter was getting a bit punchy by then.

RB's from smoothbore do tend to wander some much past 60 to 70 yards and in my experience become quite undependable at longer ranges. A good slug should do better... but I'm still looking...

Longbow

Does anyone know if any of the BPI loading manuals cover large RB loading recipes?, or are these loads just worked up based on payload weight?

Thanks
Scott

Don't buy the BPI manual, its not good. The .678 round balls are easy, just use 1 1/8 oz load data. The .735's I'm using 1 3/8 oz data, but you need to modify the wads, so not nearly as safe.

I found that shooting slugs over cushion legs (petals cut off) didn't work well for me with the Lyman Foster slugs (book load info), 0.735" Rb's or my home made TC HB slugs. A plastic gas seal and hard card wad column has worked best for me with at least one 1/8" nitro card wad under the ball or slug, plus balls like to sit on COW or cornmeal cushion.

Longbow

I like the BPI Slug manual and Buckshot manual

The main problem I have with the BPI slug manual is that about every recipe uses only BPI products so limited info. I was expecting something more like the Lyman manual with a variety of components and of course slug specific. It is still good info and not very expensive so it is added to my collection.

Another good source of info it the BPI Bucksot reloading manual. Much the same as the slug manual using mostly BPI products but useful for both buckshot and equal weight slug data.

I actually prefer their data sheets of which I bought several and should re-look at what they have now. They are also inexpensive and useful.

I collect everything I can find with slug reloading info. Not quite sure why I am so obsessed with slugs but there you go! I am, plain and simple (and I am pretty simple!).

Longbow