20 USH Problem - Long winded

[rlelvis]

Been a while but back with a problem.  Hope there is a solution out there I have not thought of or that I missed in the FAQ section of the forum.  Long read though…

I have a USH 20GA, pre Ultragon rifling (I belive 1 in 28 rifling), Burris Fullfield II 2x7 on Warne Maxima Med rings that WILL NOT GROUP at all.  I have worked on the forend and there is no contact, I have added an O ring and taken it back out, I have shimmed the rear and taken it back out, I have checked the mounts and they are tight. I have ‘backyard’ lapped the bbl manually. I have not worked the trigger but it is not the worst I have seen and from a rest on a bench is not the culprit.  The first group last year was out of the box borsighted with Rem AccuTip and was around 2 in @100yds.  I did not do anything else till this year and now cannot get anything but Rem copper Solid to group, about 2 in at 100.   Everything else is all over the place and I mean like 14 in groups!!!

I know that 2in @ 100 is good and better than good for MOD (minute of deer) but want to be able to shoot faster/flatter slugs then the copper solids.  IMHO once you are below 1000 ft lbs you are at the limit of ethical shots so that limits the gun as it is right now (-100 yds).  

I have tried Winchester 2 ¾in Supreme, Fed Barnes Tipped Exp 3in, Hornady SST 2 ¾in, Rem Accutip 2 ¾in, and the Rem copper solids. The primary difference, with the exception of the Rem Accutips, is the velocity.  My first thought is scope but I find it hard to believe that a decent quality scope would go bad or even that it would hold a group with the slower (lower recoil) and fail with the faster slugs (higher recoil?).  Plus it will consistently group with the slower slugs even after the faster have been fired.  I have tried cleaning after every shot and also leaving the bbl dirty for 5+ shot strings.  I have waited between shots for cooling and have fired in fairly rapid succession.

After $250+ in ammo and many trips to the range I am at my wits end because I know this USH should, and can, shoot better.  At this rate I will double the cost of the gun before the first hunting trip with it.

Any thoughts or similar experiences and solutions would be GREATLY APPRCIATED!!!


FWIW I have a 12GA USH that will hold sub 1in MOA if I do my part.  The best I have gotten with it was just under ½ with Fed Barnes Exp Tipped, 2 ¾in.  
Plus I have had two other people shoot the 20 Ga and no better groups.

[spikehorn]

I have a Tracker II 20ga and a 20ga USH neither gun likes the higher velocity slugs Hornady SSTs of the federal Barnes expanders. The Tracker II likes the 2 3/4 Lightfield hybred express and the 20ga USH likes the 2 3/4 buck-hammers both are rated at 1500 FPS. I tried the Remington solid coppers in both these guns and they didn't do well either. The Tracker II shot three shots into two holes touching at 75 yards, and the 20ga USH shot a three shot 1 1/4" center to center clover leaf at 75 yards. Keep trying different sabots,and shoot them for group size before you even start to sight your scope in. These guns have proven to be exceptional shooters once you find the sabots it likes.

[Thunder]

It looks like you have shot a lot of rounds thru the gun. When you say you cleaned the gun, are you using a good copper/ plastic solvent like No 9 copper solvernt. I found years ago shooting sabots will gum up a barrel real bad real fast and a standard cleaner / solvent will not touch it. I also feel a freshly cleaned and oiled gun from my experience will not place well. It must be a barrel and not a scope issue if the slower slugs group well.

[rlelvis]

Well another few (several) boxes today and back to the Rem Accutip for the best group.  Tried the Lightfields and they were 2 1/2" (two five shot groups) and the Rem Copper Solids were about the same.  But the Rem Accutip were sub 2" with a 8 shot group (throwing out a pulled flyer) I had three in one hole and two in another (1 1/4" from the 3 shot hole) and then two slightly off and the flyer.  This has me realy frustrated because the advertised velocity of the Accutips is 1850 and none of the others in the same range would even group.  And when I say that there were some of the Fed and Hornady that MISSED the target at 100???
I would still like to try the Fed 2 3/4" Barnes Expander but have not found them locally. 

And when I say cleaned I was running a brush through several times and then a tight patch with a Plastic solvent through it.  I also tried the brush and then a oiled patch. There was no appreciable fouling, verified at home with a detailed cleaning.

I appreciate the thoughts on this it might just be one that will not group great, no matter what is done or what is fired.  It is within MOD so I will give it a try in the next few weeks. 

Might be time to try another 12 GA and if I get a good one put this one on G Broker.  So watch for the same user name selling a 20 GA USH...