Losing my mind? Rem 870 20 gauge, Fed Prem TSS 7 and 9, Carlson TSS choke

[TeeGee]

I patterned the Federal Premium Heavyweight TSS with the mixed shot #7 and #9 the other day, at 40 yards, got the image on the right.  I was happy with it - at that range it was a nice even forgiving pattern, but with plenty of killing pellets. 

Then, I was working on sighting in a new red dot sight, and for my final step I took a shot with that same ammo at 40 yards, and got the pattern on the left.  As you can see it's MUCH less dense. 

This is with the same gun, Remingto 870 express, same choke, Carlson's TSS .555.  It was a different day, different temps, the gun had been shot a dozen times in between, so maybe those factors count.  I'm fairly new to all this so I don't know much about this stuff.  But would it change THAT much? 

I thought maybe I was losing my mind and I'd somehow used different ammo.  But as far as I can tell, from digging through the spent shells, it sure looks like I was shooting the same ammo. 

Should there ever be that much difference shot to shot?  Could the different days have accounted for it?  I'll go try it again at some point, but I don't want to keep shooting this expensive ammo...

[hootgobbleyelpgobble]

You need a larger back drop when using those little targets to get a true center of pattern in my opinion. Take some cardboard, newspaper, gift wrapping paper, etc. and place your smaller target in the center of them. You should be able to see what the gun is really doing then.

Also i tried a 555 in my 20ga 870 and it was blowing the pattern. I had to open it up some and really picked up the numbers I wanted.

[FL-Boss]

first,  don't shoot turkey targets. Get some white poster board or big box  ..put a round dot on it and shoot that so you can see the complete pattern.
Second, clean your barrel real good between each shot.  Most guns will shot better with a clean barrel, but I have seen some that shoot better with a slightly dirty barrel. The wads of these shells leave a ton of plastic junk behind. Either way.... by having it spotless clean for each shot, you have a consistent baseline.

[nyhunter]

Use denatured alcohol for the cleaning solution that way you wont have any oil left in the barrel.  Make sure you remove the choke and clean it separate  from the gun otherwise all that plastic will end up in your choke, I just put in a I.C or Mod. choke in the gun to clean the barrel, 

[Liljake]

The dozen shots may be cause of you pattern falling off. Also were the temps colder?
The previous members who posted offered some great advice. Get your barrel squeaky clean and shoot a round. If you're happy with the pattern you know you need a clean barrel. My Mossy 500 needs a squeaky clean barrel to throw a great pattern. My h&r single shots like a slightly fouled barrel. 1 round then bore snaked with no alcohol to throw their best patterns. After 4-5 shots my patterns really start to fall apart. It's frustrating and expensive to get where you want to be with your pattering. That's why once guys find a load/tube that shoots great they stock up on ammo with the same lot number.

[BandedSpur]

I clean my barrel thoroughly between every shot with expensive TSS ammo. I imagine that is your culprit.

[TeeGee]

Ok, thanks everyone.  I had no idea I'd need to clean that often.   I already know this is a dumb question, but while we're on the topic: is it just the barrel that I need to clean for this?  Is there anything else I need to clean as regularly?  I figure once this season is over I'll break down the gun and clean everything...?

[N2TRKYS]

I've got an 870 and I don't clean mine that often.  I wouldn't be happy with either of those at 40 yds. 

[paboxcall]

My Mossy 500 needs a squeaky clean barrel to throw a great pattern. My h&r single shots like a slightly fouled barrel. 1 round then bore snaked with no alcohol to throw their best patterns. After 4-5 shots my patterns really start to fall apart.

Exactly my experience as well. My H&R single shoots well with a slightly fouled barrel. I shoot a trap load through it at the beginning of the season then hunt it, clean it at the end and repeat next year. And my Mossberg 20 gauge needs a clean barrel - after three rounds my pattern at 40 opens up so it gets cleaned constantly.

[Ranman]

How about an update in your progress.. I shoot the Carlson's.575 in mine, and it performs well.

[TeeGee]

I cleaned it, and it seemed to help.  But I didn't try a comprehensive test because I've been waiting on a new sight and wanted to do both at the same time, especially since that particular shot is so expensive.  I'll let you know... but my initial test said it probably needed a cleaning, or something else got wonky that day. 

[PharmHunter]

Federal TSS is terrible, period.  I have been surprised since it came out at the extremely poor performance out of such a big and reputable ammo company.  Thought originally it was a fluke or they'd get it straight, but multiple calibers and years now...same pathetic patterns continuing. 

[Old Timer]

There`s an old saying: She ain`t what she use to be! A friend of mine contacted them about a round that the shot did not come out of the wad, he was using Grand Slams. Never experienced that. The answer was you should try our tss.