Matching my bullet with its best-fit sabot

[RoJo]

I have thompson omega from the first year they came out, my question is the primers are black after a shot from what i read they shouldn't be and can effect accuracy, so how do i fix that

I’m still looking for that answer. First shooting CCI 209M) I inadvertently did not clean my BP, through 30-40 shots. Some say I shouldn’t have to. The last 20 or so gave me sooty primers. Second trip, I cleaned the BP after each 5 shots - just because, and to give the barrel a break in the 95 degree heat. Virtually no sooty primers or residue in the area between primer and firing pin.

This week, went from 70 gr by weight to 77 gr by weight. Virtually all primers were sooty, some were very sooty. Responders suggested using O-rings, shims, changing primers, purchasing an Arrowhead BP replacement kit ($200 +).

CCI tech says it is normal for primers to get sooty. Why sometimes and not always? I will find the answer somewhere. I’m wondering if the flash hole is somehow defective in size. I’m trying to recall what I did differently between my second range day compared to the first and last. In the meantime, I bought some Federal primers to see if they make a difference.

 

[ronlaughlin]

For an old rifle like yours, one may suspect the breech plug is worn. The flash hole may be too large/worn. The flash channel may be plugged. The primer seat may be flame cut or just dirty. The primers you are using may be too short for your head space.

My Omega(s) don't produce black primers, because they get nice clean newish breech plugs, and measured primers. Only W209 primers that are 0.302" or longer are used. The actions of the Omega(s) are tight.

Underclocked explains how to tighten Omega actions HERE

 

[ShawnT]

I don't have an omega (Yet) but there are several Omega shooters on here.

Which primer are you currently using? The Win209 is one of the longest. So if your using something like the CCI, or other shorter primer, give the Win 209 Blue Box a try. Has yours been shot a lot and have you modified it for a ventliner yet?

Not sure if you can add an oring to yours without deepening the primer pocket or not.

I just saw Ron Chime in . He has a lot of experience with the omega.

 

[DaveyKBC]

I read recently about sizing a rifle barrel ID. Apparently you must use a pure lead "ball" slightly bigger than your actual bore (as has been said earlier) Forcing is down the barrel using a brass rod drift shouldn't cause any barrel damage as the lead is much softer than the steel barrel (& isn't that what happens every time we fire a rifle?) once the slug emerges from the barrel it can be measured with micrometer etc. Not sure I'd want to try it, though comparing the hardness of the materials involved it "should" work. Famous last words!

 

[MrTom]

The first thing here is that the heavier charge is telling me that you do in fact have a sealing issue RoJo. I use Winchester [blue box] primers and see little if any primer fouling at all in any of my CVA guns. I've converted the plugs to vent liner use for the 209 powder and still have clean primers after firing. I don't care for CCI primers at all and use only the Wicnhester primers as others have also alluded to. You need to use longer primers than what CCI offer or you need to put the rubber o-ring in the plug every 15 shots or so to see if they'll help. Send me your mailing info thru personal messaging here and I'll send you a few O-rings to try.

 

[RoJo]

The first thing here is that the heavier charge is telling me that you do in fact have a sealing issue RoJo. I use Winchester [blue box] primers and see little if any primer fouling at all in any of my CVA guns. I've converted the plugs to vent liner use for the 209 powder and still have clean primers after firing. I don't care for CCI primers at all and use only the Wicnhester primers as others have also alluded to. You need to use longer primers than what CCI offer or you need to put the rubber o-ring in the plug every 15 shots or so to see if they'll help. Send me your mailing info thru personal messaging here and I'll send you a few O-rings to try.

Thank you for the feedback. Do you have any experience with the Federal 209A primers? The gun shop I frequent didn’t have any Winchester primers. When they’re in stock they’ll sell the 100-count boxes. The local Field and Stream had a box of 1000 but I don’t want to buy that many until I test them. I’ll get some at Cabela’s this weekend. I did buy a 100-pack at the gun shop just to see if here is a difference.

One day, maybe I can answer this question for someone else, but in the meantime, what allows the CCI 209M to ignite cleanly in other Accura’s But not mine? I’ve seen many testimonials of ML using O-rings to solve the problem. I sent you my address in a pm. I will gladly return the favor. Thank you.

 

[MSalyards]

Adjusting or replacing the o-ring by the firing pin can make a difference. They need to be replaced .

 

[kb2112]

From the Barnes website:

“To re-cap bullet and sabot packaging, the Barnes MZ Expander line is packaged with the MMP black HPH 12. The T-EZ is packaged with a blue version of MMP’s HPH 24; however, the MMP HPH 24 sold to consumers is black. The MMP HPH 12’s and HPH 24’s sold to consumers are both black and can be easily confused. Connie at MMP says the secret to telling them apart is by the number located in the hollow stepped base of the sabot. It is a hand written number for the HPH 12 and the HPH 24 has a more squared or typed number in the base.”

Try swapping sabots.

 

[DaveyKBC]

I came across this recently, It gave me a better understanding of the ins & outs of Sabots & Bullets. But I guess it will only work if you have access to the various types & sizes (which I don't!) Hope it helps.