Accuracy Change?

[Timberelk]

Hello All,

You all helped me years ago find a good load for my TC Omega muzzy. Turned out to be 70 grains weight BH 209, harvester sabot and 300 grain Hornady XTP. Accuracy was great at 100 and I shot a few other rocks at further distances

Fast forward to last fall I tried some longer shots at 200 on paper. While the XTPs grouped well at 100 yards, 200 yards the group was all over the size of a dinner plate, maybe bigger. I changed over to the Hornady SST 300 grain and the groups tighten right back up to 3 or 4 inches at 200. I was good to go and took a deer at just under 200 yrds last year

Fast forward to this week and I go out to verify the rifle is still on. Have gone out 3 different days. Right away at 100 yrds groups aren’t great, 3” or so at 100 yards. Just because, I then tried it at 200 yards and the shots are all over the paper, not pattern

Only thing that I can think of that changed is I misplaced the breach plug I normally use and had to start using a back up plug that I got with the gun when I bought it used many years ago. I’ve noticed more blow back black soot around the nut of the breach plug when I go to clean it. I don’t remember that happening on the original breach plug.

I calledT/C and they not longer make breach plugs for my muzzleloader (I may be able to find one on eBay).

I’ve checked the action bolts, the scope (Nikon prostaff) is still tight and doesn’t appear to be moving, I checked the ring screws and they are still torqued

Any idea what could be throwing off my groups?? So weird that I haven’t had issues in the past and the 3 times I try to shoot it this year I can’t get it to shoot well

 

[Timberelk]

Maybe plastic fouling is creating my accuracy issues..?

 

[ElDiablo]

Check to see if the flash hole is eroded and that the flame channel is clean (carbon drilled out). That’s likely the issue

Are you using a different lot of BH209? If you’re weighing your powder you’ll need to consider that weight varies among lots of Bh209 - so 70 grW with one lot isn’t the same as 70 grW from another lot.

Yes, lots of OEM style plugs available on eBay or do yourself a favor and pick up Woodmans adjustable breech plug for the Omega!

 

[Timberelk]

Check to see if the flash hole is eroded and that the flame channel is clean (carbon drilled out). That’s likely the issue

Are you using a different lot of BH209? If you’re weighing your powder you’ll need to consider that weight varies among lots of Bh209 - so 70 grW with one lot isn’t the same as 70 grW from another lot.

Yes, lots of OEM style plugs available on eBay or do yourself a favor and pick up Woodmans adjustable breech plug for the Omega!

Thanks for the info. After my first of my 3 trips so far this year, I drilled out the flame channel as it was very corroded. The flash hole has been clean for all 3 shooting trips. I would say there may be a little bit of erosion but it’s minimal. I didn’t see accuracy improve after drilling out the carbon in the flame channel

I am using different lots of BH 209. I have 3 separate bottles that have +- 20 % left in each. Hard to go pay $80+ for a new bottle. I have been only using the same bottle for these 3 shooting sessions but I don’t believe it’s the original bottle that I used to find my original accuracy load. And I’m not sure which bottle I used last year when I got the 300 grain sabots to work

I do potentially have a solution to test if it’s the powder. I have 6 or so tubes left over from hunting last year that I can test and I believe I know which bottle of 209 I originally found my accuracy load with 5 or so years ago. If it does end up being the powder. I will have minimal “good” powder left so I’ll likely need to get more BH 209 and refind the accuracy load

If you were guessing, do you think it’s the powder or the breach plug?

 

[ElDiablo]

If you were guessing, do you think it’s the powder or the breach plug?

I think the plug has the potential to cause bigger issues. Can you check the flash hole size with a torch tip cleaner and caliper? OEM plug flash hole should measure about .030”.

Then you’d know for sure.

 

[ENCORE50A]

I'd do a box test with that scope.

 

[Timberelk]

I'd do a box test with that scope.

Not sure I’d trust it to dial repeatedly but I’d trust it (for the most part) to hold a zero. Or at least I hope lol.

Right now I’m leaning toward the plug, really wise I could find my original plug but I’ve torn the house up looking for it already

 

[ENCORE50A]

Not sure I’d trust it to dial repeatedly but I’d trust it (for the most part) to hold a zero. Or at least I hope lol.

Right now I’m leaning toward the plug, really wise I could find my original plug but I’ve torn the house up looking for it already

If you can't trust it, replace it. Scopes go bad and if it won't dial, throw it out, as Nikon doesn't make scopes now.
Seriously, if you don't trust it, replace it.

 

[Timberelk]

I think the plug has the potential to cause bigger issues. Can you check the flash hole size with a torch tip cleaner and caliper? OEM plug flash hole should measure about .030”.

Then you’d know for sure.

Yeah I can for sure, just need to go get a torch tip cleaner.

I did have some flux core .035” welding wire that I tried to get it to fit in the flash hole and had no luck getting so it looks like the hole is smaller than .035”.

Is that good enough info to say it’s not enlarged or are we talking more along the lines of .001 or .002 can be causing this issue?

 

[Timberelk]

If you can't trust it, replace it. Scopes go bad and if it won't dial, throw it out, as Nikon doesn't make scopes now.
Seriously, if you don't trust it, replace it.

I agree and that’s the way I am with my rifle scopes because I’ll shoot out to +- 600 yards.

I only meant I don’t trust this one to dial because it’s cheap, like $200 5 years ago and cheap scopes don’t track true. I really only believe high end scopes like night force actually track true. I do have a VX2 luepold I have laying around I could throw on there but then I’ll be burning through the last of my BH verifying acvruxy and sighting in the gun. Side note, I read one of your posts about T7 and BH from last year and I’m considering making the switch if I need to be redialing in this muzzleloder

I was just hoping I could find an easy solution without changing things up because I only use this muzzy to hunt very few times and I had thought I had this gun figured out (many trips to the range and posts this forum 5 or so years ago)

 

[Timberelk]

I wanted to mention something on the powder

These last 3 days I have been using BH 209 that was bought last year. I can tell because it has Hodgdon on the bottle. Wondering if like Eldiablo said, 70 grains back 5 years ago is not the same as 70 grains from a bottle from last year

This was the same bottle I believe I used last year when my 100 yrd shots with XTPs were good but 200 yards were not. That’s where the SST step in and fixed my groups at 200 yards

 

[ENCORE50A]

Buy a bottle of T7 and do the box test. Yes, an eroded flash hole can cause issues, but IMO its highly unlikely if its throwing them all over the place. Generally....... an eroding flash hole will take a 1/4" group and open it up to 1/2" group and the more it erodes the larger the groups. But......... it doesn't shoot good one day and throw bullets all over the next.
Save your BH and test the scope with T7. Nikon had good glass but their scopes failed quite often.

 

[ElDiablo]

I did have some flux core .035” welding wire that I tried to get it to fit in the flash hole and had no luck getting so it looks like the hole is smaller than .035”.

Is that good enough info to say it’s not enlarged or are we talking more along the lines of .001 or .002 can be causing this issue?

If it hasn’t eroded beyond .034 or .035, then you’re probably ok. Guys say .037 or so is the time to replace a plug.

 

[jsteurrys]

If it hasn’t eroded beyond .034 or .035, then you’re probably ok. Guys say .037 or so is the time to replace a plug.

I replace mine at 0.036".

 

[Timberelk]

Buy a bottle of T7 and do the box test. Yes, an eroded flash hole can cause issues, but IMO its highly unlikely if its throwing them all over the place. Generally....... an eroding flash hole will take a 1/4" group and open it up to 1/2" group and the more it erodes the larger the groups. But......... it doesn't shoot good one day and throw bullets all over the next.
Save your BH and test the scope with T7. Nikon had good glass but their scopes failed quite often.

To do an accurate box test, doesn’t one need to first establish a load that is accurate? Otherwise you don’t know if it’s the scope or the rifle throwing bullets astray?

 

[ENCORE50A]

Eliminate one possible contributing factor at a time. Changing a breech plug ONLY, shouldn't start throwing bullets all over the place, even if the flash hole has enlarged. Will it affect extreme accuracy, sure, but not throwing bullets all over the place. If you have a proven load and bullets are not hitting the POA, or as in the recent past, then the highest possibility is that the scope has went bad. A scope can be perfect for "X" amount of rounds, even while you're at the range, then with the next round, everything go all to heck.

If you turn those turrets and it doesn't track, there's your sign. There is no magical fix that any of us can provide you. Test the scope.
In years past I've had multiple Nikon Monarch scopes take a ship on me. I've had Leupold scopes bust on me. I had a VX6 that took a ship, I sent it in and they "fixed it" and in just a few rounds it broke the erector system again. I won't shoot Vortex scopes, as I've busted the erector systems in those too.

 

[Timberelk]

Just wanted to provide an update before I start changing things up like a new scope or plug.

The yellow numbers are from this morning at 200 yards with the newest bottle of BH209 from last year. The red numbers are this evening at 200 yards with my original BH 209 bottle from 5 or so years ago.

So I believe I’ve ruled out the powder from the equation because it’s all over the target regardless which bottle I used. For reference, with my centerfire rifles I can usually shoot 2-4” groups at 300 yards so I don’t think it’s the shooter causing this issue.

Before I go the route of putting a different scope on the gun, anyone think I should try a new plug first? eBay plug (after market, not made by TC) takes about a week to get here and I have about 3 weeks until the season starts. Scope doesn’t appear to be moving in the rings as I marked the scope and rings years ago with a sharpie

 

[jsteurrys]

Replace with a known good scope and shoot at 100 yards. Verify that the action screw(s) is/are tight. Make sure the flash hole is not larger than 0.036". Which primer are you using?

 

[Timberelk]

Replace with a known good scope and shoot at 100 yards. Verify that the action screw(s) is/are tight. Make sure the flash hole is not larger than 0.036". Which primer are you using?

Cheddite 209 primers

 

[Kevin C.]

Hello All,

You all helped me years ago find a good load for my TC Omega muzzy. Turned out to be 70 grains weight BH 209, harvester sabot and 300 grain Hornady XTP. Accuracy was great at 100 and I shot a few other rocks at further distances

Fast forward to last fall I tried some longer shots at 200 on paper. While the XTPs grouped well at 100 yards, 200 yards the group was all over the size of a dinner plate, maybe bigger. I changed over to the Hornady SST 300 grain and the groups tighten right back up to 3 or 4 inches at 200. I was good to go and took a deer at just under 200 yrds last year

Fast forward to this week and I go out to verify the rifle is still on. Have gone out 3 different days. Right away at 100 yrds groups aren’t great, 3” or so at 100 yards. Just because, I then tried it at 200 yards and the shots are all over the paper, not pattern

Only thing that I can think of that changed is I misplaced the breach plug I normally use and had to start using a back up plug that I got with the gun when I bought it used many years ago. I’ve noticed more blow back black soot around the nut of the breach plug when I go to clean it. I don’t remember that happening on the original breach plug.

I calledT/C and they not longer make breach plugs for my muzzleloader (I may be able to find one on eBay).

I’ve checked the action bolts, the scope (Nikon prostaff) is still tight and doesn’t appear to be moving, I checked the ring screws and they are still torqued

Any idea what could be throwing off my groups?? So weird that I haven’t had issues in the past and the 3 times I try to shoot it this year I can’t get it to shoot well

You need a BH 209 specific plug.