What a weekend...yuck (omega)-update!
 

well, where to start.

I had all the time, powder, and bullets I needed for an extended shooting session and was determined to get the ol Z omega (syn/blue) shooting like I had seen it do before (say 2'' groups at 100),

Its topped with a nikon prostaff. I was shooting 120 gr of pyrodex pushing a 250 gr shockwave (the same set-up of used with this thing since I bought it 3 years ago....probably has had no more than 100 shots through it). Barrel was clean as a whistle. all screws everywhere were tight. After a couple initial decent shots the whole thing fell apart...made you want to cry....after a dozen shots with only a "click" or two here and there on the scope, the group was barely inside a pie plate at 100 yds. I was cleaning it after every shot...then I started doing it after a couple or three shots...didn't make any difference...bullets were flying everywhere...up, down, sideways. Even though I had a spotting scope I was walking down range every shot or two....barrel temp (if that is ever a problem on a m/l) certainly was not a problem here.

To top it off, I had a brain fart and double loaded it....session over.....took the breech plug out...couldn't get the jammed loadS to move. Went home, took the air compressor to it to blow out the powder from the first load. Couldn't budge the thing with a mallet.

yesterday I took it to a friend who is an expert at BP rifles. We got the bullets pulled and the block cleared. He said the accuracy problem might be the pyrodex if it was old (it was...couple years...although stored in a cool dry place....it looked fine). He gave me some goex FF bp and said try that.

Do you guys think older pyrodex (even though it looked perfect) could be deteriorated to the point that it effects accuracy like this???

I've only now got a couple days to figure this out before the first special deer season ends....I would not really feel comfortable taking it hunting with the accuracy problems it is having unless I kept the shots really short.

I know this thing will shoot...but something certainly is wrong at the moment.

I had it go out of whack one other time and all it needed was the bedding screws tightened...but this time everything was already tight.

the only other thing I've done different then those first great range sessions is quit using bore butter between shots (based upon recommendations from this forum) and AFTER that decision it still shot good

any other thoughts??

sorry this post is sooo long

thanks
hb

Initially i did not know i double loaded it (although i knew something was wrong)...I thought it just jammed with a single load and i was going to have to send it back to t/c. Also I WAS going to ask them to take a look at the barrel....my point is I took the scope, rings, and base off...so i get to start totally from scratch again...lol

Absolutely. I would bet the powder is your problem. Either that or your scope has gone bad. Give some new powder a try and let us know how it does. May want to try some Black Horn 209 powder.

Lacking some information necessary to determine the cause of your problem I will point out some possibilities to look at: if the stock to action screws on a Omega are over tightened it will cause problems especially on the plastic stock. If the touch hole in the breach plug is flame cut out especially if it is irregular can cause your problem. The best solution for that is to replace by drilling tapping and putting in a vent liner.
And yes even good stable old Pyrodex can sour if exposed to moisture long enough though it is not near as bad as the APP powders, the only powder I would trust to set any length of time is Blackhorn. The best answer to that is open a brand new can and try it. There is also the possibility that the scope has been dropped or banged some stand up to this better than others but if a gun is dropped or knocked over and it bends the barrel of the scope even a little the parallax induced will cause the results you are experiencing.

I'd test with irons and use loc-tite upon re-mounting the scope.

Check the amount of how hard you are tightening down the lug screws. Also I would pick up a new pound of powder. If this shot well with that powder and projectile before, then it should again. I would do the powder and remount everything nice and tight.

I'm no expert on problems like this, but there might be some wisdom in backing off on the charge to 90-100 grains and see if it improves accuracy or group size any.

thank you gentlemen for all your quick replies. Lemoyne, the breech plug looked good to me and the ignition hole too (round, that is). I cleaned that thing thoroughly before this last round as well. I'm not exactly sure but guess that "flame cut" means the hole is distorted in shape, which it is not. Scope/gun have never been dropped or bumped.
As far as the lug screws...they are as tight as I can get them with regular screwdriver....I don't know how else to do it.....and remember that the last time I tightened them solved my accuracy problem at that time...and i haven't moved them sinse....although I did just check them again to make sure they were still tight.

One thing I noticed when taking the scope base off was that thos screws were extremely easy to "back-off" I thought they might have not been tight enough.

I know you guys may think this is a dumb question but, lock-tite....I've never used it.....can you still remove a screw if you need to after you use it??? Do you guys use lock-tite on all your guns when it comes to scope bases and such. Perhaps I need to buy a torque wrench...if so what poundage should I use for lug screws??? how much for scope screws???

I didn't realize you could over-tighten lug screws. how is that possible??? especially with a syn stock??

Several types of loc-tite, with different strengths, some are permanent. Get the BLUE version to keep screws tight but still be able to remove them when needed.

I have it happen to me more then once long long story short the scope was saying good buy
I would try the gun with iron sights and see how she shoots

I have used Loc-It (blue) on all my scope base and ring screws for many years. It makes the threads "sticky" so vibration won't loosen them, but they are removable.
IMO it isn't really necessary to torque screws down REALLY tight. As long as all play is removed and they don't come loose, tight is tight.
As to your question about overtightening a synth, stock - even the strongest plastic can bend and/or warp under enough pressure.

yes, but can you over-tighten the lugs by hand with a screwdriver???

Yes indeed you can. I usually tighten them until they snug up, then another one-quarter turn.

Lot's of good possible solutions have been suggested. I can only speak for my Z5.

I had a similar issue and found I wash pushing the 250"s too fast. I went with a 300 gn. bullet, Harvester Short Blacks and 110 of T7.

This combo produced 1.5" groups at 100 meters from the lead sled.

Try slowing things down and as a previous poster suggested.

thanks semi (and the rest of the responders to this point).

can anyone explain why tightening to much is detrimental. I'm guessing that it does not allow the barrel to oscillate (sp) correctly during the shot or something but really have no idea and did not previously know that it was possiblef for them to be to tight....should I use loc tite (blue bottle)on the lugs??

how about the torque wrench idea for precise tightening.

I know right now the lugs are as tight as i can possibly get them by had with a screwdriver..so probably not right

thanks again all
hb

There is two reasons. In the plastic stock it can crush and distort some of the supports. Also it creates tension and changes the vibration [whip] of the barrel and so the bullet exits the barrel at different points of the vibration which causes it to be pointed a bit different.
The stock to action screws should be set at 28 inch pounds .

I have a synthetic stock Omega (older stainless one before the Z-7 came on the scene). It was a tack driver for about 50 shots then everything went to s%&t (crap). I believe it is the stock to action fit. It needs to be bedded to fix it but I have other rifles that are better out of the box so I have not addressed the Omega. It went from being my favorite to becoming my least favorite. Personally I am done with T/C rifles. The front lug is screwed on my rifle and with the screw tight the lug still moves from side to side. Not impressive for the cost of the rifle. You might check both of those items on your rifle.

If you are in a hurry and cannot bed the rifle before a hunt. You might try checking the barrel to stock and see if it touches on one side and not the other. If your barrel touches you can just put some shims under the front lug to space the barrel up and that might get you out of trouble for a short time at least enough to do your hunt.

Seems that cutting the screw shorter would fix this issue.

thanks again everyone for the replies...I'll let you know what happens. Looks like I'll shoot it tomorrow or Friday and then go hunting (assuming that the accuracy problem is corrected) on fri or Sat. Shouldn't need much time to find a fat doe in the wide open around here....just need a gun that I can use with confidence when pulling the trigger. take care all

Good luck.. it will be interesting to hear of your results.

Update
 

Greetings all.

Back again to report on the outcome of this deal.

Cleaned the gun spotlessly. Took the barrel off and shimmed it with some camo duct tape (free-floating exercise) as I thought just one of the sides of the syn forearm was rubbing it a little. Git the idea from semisane's thread. Snugged the lugs with lock tite (blue bottle). re mounted the scope from scratch using lock tite (on the actual mount only).

New Load:
250 grain shockwaves. 100 grains of goex FF bp. Shot respectable groups at 50 yds...1.5 in or so. Not perfect, but something I could live with short term.

shot about 8 times and was able to get the poi to walk to the bull...like you would expect

downside: after going through all this, I finally got to go hunting on Sat. No deer offered a reasonable shot...only saw a couple. high for the day was 87 degrees...not what you'd call prime hunting weather...LOL....full moon to boot (waning gibbous, practically full). oh well

upside: In the final assesment, I feel I can trust this gun again. I think it may have been the old pyrodex. still looked fine but......

I'm gonna stick with regular ol BP for a while. On another note, my shipment of "no excuse" conicals arrived. 100 of them (460 grain)...yeah baby. I'm looking forward to getting on the range with them and using them during the regular season in Dec. (early season is closed now). Hard to believe the way that gentleman does business. sends out the bullets with an invoice to pay...no cc to secure payment...nothing...over the internet....must be a very nice, forthright guy.
Anyway, if anyone can recommend a good powder load for these that'd be great.

generally, how much would you guys expect to pay someone to do a bedding job on a rifle like this?

thanks for all your alls help