Breech plug accuracy effect???

[smong2000]

This has been on my mind for a while and I thought I could air it here for some feedback.
Has anyone really seen breechplugs affect their accuracy and if so how much?
I have T/Cs and have been shooting one old plug in several rifles for years. I got it on a project barrel, it's pitted and looks terrible and has some real bad firecutting. It has the large dome that goes clear to the edges and I liked the way it worked with loose T7 and now with BH209 so kept switching it from rifle to rifle when I go to the range. I just bought a new plug because the fouling was geting past the primer and making a mess and figure it 's time to retire it.
I never saw any accuracy problems with my Encores or Omega and would have noticed because I expect sub MOA from 2 of these rifles. It never seemed to matter whether I used 25ACP BP, large dome or small dome BPs . I can't recall if my POI was different with the different plugs because I don't pay much attention where groups are printing until the final sighting with my exact hunting set up and usually tweak it a few clicks every season. Thanks

 

[paia]

I have been shooting Omegas for years--one has close to 2000 shots through it with Pyrodex and 777, and the second Omega has about 700 shots through it--a few with Pyrodex and 10 containers of BH209 have been shot through it.

A few years ago I read somewhere that when the "flash hole" of the breech plug starts to erode and open up it will adversely affect accuracy. I have changed my breech plugs about every 300 to 400 shots (once a year usually) and both Omegas regulary shoot sub-1" at 100 yds with loads they like.

This is just a maintenance thing I have done--I cannot say that I ever had accuracy problems that I could blame on a worn BP, but my Omegas have always shot beautifully and I have kept doing what I have been doing because why fool with success?

I did try a 25 ACP conversion with Pyrodex and 777 a few years ago and saw no advantage to it or gain in accuracy.

With Blackhorn 209 I did some testing with primers and found in my rifle, with the loads it likes, Winchester 209's out shot Federal 209's. Those are the only two brands I tried.

When shooting a Savage 10MLII with smokeless powder I definitely had accuracy issues with the breech plug vent liners. After 60 to 80 shots of smokeless powder (I worked with N110, 5744, and Reloder7 mostly) the vent liner flash hole would erode to over .035" and accuracy would suffer. A new $3 vent liner tightened groups back up.

My Omegas could outshoot the Savage to 200 yds all day long, and the Omegas are lighter and handle better so I sold the Savage a while back.

In short, I do change my Omega breech plugs every few hundred shots, but that's just my routine--perhaps I will let 'em go a while and see if groups eventually do open up.

 

[Lee 9]

While the black powder subs are a lot slower to flame cut a BP to where it will lose accuracy they do do it. if you do a nice clean job of drilling and tapping a 10-32 thread in to the touch hole end cut the face to match and install a vent liner. A bit of Teflon tape wrapped around the threads with a drop of synthetic oil on it makes it easy to take out for cleaning or replacement. The Lehigh vent liner has given me excellent results.

 

[squirrelhawker]

When my buddy and I were designing different breechplugs for the NEF
guns we found some interesting facts. When shooting a particular gun with a plug that had a very deep powder cavity....say .380" dia. by .625" (5/8") deep...or a plug that had virtually NO cavity...the accuracy potential was EXACTLY the same. Got the same results using everything exactly the same except the plugs cavity or lack of one. Just for your info. Anybody remember some of the goofy and expensive spark plugs for your car
that were marketed years ago?? Beware! :lol:

 

[Confederate rifleman]

When I had my Omega, groups opened up after 4-500 rounds and a change of plug put everything right.The common symptons of a burnt plug are increased blowback and a general enlargement of groups . They seem to have about the same service life as a nipple.They just cost 3x as much!It didn't matter if i used 209's or a variety of small rifle/small pistol primers in Variflames,4-500 rounds was about it

 

[squirrelhawker]

When I had my Omega, groups opened up after 4-500 rounds and a change of plug put everything right.The common symptons of a burnt plug are increased blowback and a general enlargement of groups . They seem to have about the same service life as a nipple.They just cost 3x as much!It didn't matter if i used 209's or a variety of small rifle/small pistol primers in Variflames,4-500 rounds was about it

Like myself and some of the others have done.. install the savage style ventliner screw if you are able. (Not sure what your plug looks like) Savage has a patent on the idea..so it wont be done commercially for a while I guess.