Out of 3" slugs.
Which should produce the best accuracy?

Remington 3" buckhammers
( http://www.remington.com/products/ammunition/shotshell/slugs/buckhammer.asp)

or the Remington 3" premier copper soilds
( http://www.remington.com/products/ammunition/shotshell/slugs/copper_solid_sabot.asp)

The buckhammers say: superior accuracy, 3 inch groups or better groups at 100-yards.

The copper solids say: Accuracy is exceptional, producing groups of 2 ½ inches or less , but doesn't give any yardage.

Both say that they have 100-percent weight retention.

As far as performance I would choose the preminum loadings but for accuracy,NOBODY can tell for sure until you try the different loads from bench. That way,you know for sure and ain't guessing or going by somebody's opinion that ain't gunna be shooting your exact shotgun. There are always surprizes along with barrel/bore/rifling/etc differences.
Show me somebody that can tell you which load is going to be most accurate in YOUR gun every time and I'll show you a know it all or someone that posesses ESP. NOBODY knows for sure without shooting and comparing.

Robinhood, how's things over in the Emerald forest?

If you tell me what gun and barrel you are shooting I will fire up the old crystal ball and give you an answer.

But for now I will recommend the BuckHammers. With the assumption that you are indded using a fully rifled barrel, I haven't really seen the Hammers perform poorly in any gun but the CopperSolids are a bit picky.

Haven't been doing any, robbing the rich, But I'll take donations to the poor.

Mossberg 935 with mossberg fully rifled barrel.
Going out to shot right now. Let you know what I find.

i researched the crap out of this and ended up spending well over $120 in slugs trying to fing out the best round for my Rem. 870 WM pump w/24" Hastings rifled barrel. i pretty much tested everything out there but the "hastings" brand slugs which are very similar to the buckhammers. this is what i concluded. it all comes down to the twist rate of your barrel, the hastings is a 1:34 twist where as many of the factory rem & browning barrels are 1:28 twists.the 1:34 hastings seems to like the slower velocity (< 1700fps), larger bore attached sabots the best. accuallyfrom a rest, with an Aimpoint red dot sight i could consistantly shoot 1" clover leaf 3 shot groups @ 50yds with the 3" buckhammers. they shot best in MY SETUP. brenneke golds, and 3" rem copper solids also shot notably well but not as well. but once the muzzle velocity gotover 1700fps, the accuracy went down the drain. core lokt ultras, platinum tips, partition golds, and the ever so popular hornady sst's shot HORRIBLE, as they had flyers everywhere. but i beleive it to be due to my barrel twist of 1:34, i know may guys with rifled barrels in a 1:28 twist that shoot those slugs with great accuracy. it all depends on you barrels twist rate.

The copper Solids are not good slugs if you are planing to shoot distances and the groups i got were about 2.5in at 25 yards. I use Federal slugs. They cost a little more but have alot less drop and more accurate.

Well, I just got back from the range. It is a 50 yard range.
I shot both slugs and grouped them about the same ( 1" - 1 1/2" ) groups.
Placement was different, would need to decide which I will go with and them sight it in.
Buckhammers shot more right and down them the copper solids.
But like I said both grouped equally.
Any info for knock down ?

All depends on your gun and what distances you want to shoot. At 50-75 yards most will probably shoot fairly well. Once you get to 100 yards things get a bit dicey and the guns get pretty picky.

Most rifled shotgun barrels don't care for the light fast projectiles. They just don't have enough twist is what I would guess. Try to stay around 400 grns or more and around or under 1700 fps. That doesn't mean all guns are like that though, some do pretty well with the faster stuff. Never hurts to try if you can afford it.

NEVER go by what the package says. There is NO WAY they can guarantee accuracy in any way shape or form. Every gun is different and will like different ammo. You just have to experiment until you find something you like.

I would try Hastings, winchester BRI and the platinums (those babies kick!), and some brenneke. Lightfields wouldn't be bad to try either.

Just some suggestions any way.

Paul

Just for the heck of it try plain ole Remington Sluggers, yep the $1.99 a box for 5 slugs. I get great groups with my 1187 with a rifled barrel and took my last deer at 137 yards. It's worth a try in my opinion.

Another vote for the Federals.

I have done the cornicoupia of slugs thing and when all is said and done the federals grouped the best out of my rig (Browning BPS + Hastings fully rifled barrel). They kick like a mule (not as bad as the buckhammers or the old Brenekie Rotweils) but significant.

At the range they will make a nice cloverleaf at 50 and about a 2 1/2" group at 100 (shooting from a sled).