I was cleaning my new Accura's breechplug and noticed the flash hole was really small so I compared it to an extra plug for my Kodiak and the Accura's is about half the size as the Kodiak. Does anybody know if it would be better to use the larger or the small holed plug? Would it hurt anything to use the larger holed plug in the Accura? The larger holed plug is a replacement plug from CVA so its not been worked on.
Flash hole size?
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I will compare them tonite.
I have an original Kodiak plug, a OEM Acurra plug and a new in box CVA plug thats a month or two old. The Kodiak/WinApex plug does have MANY more shots through it so it may have some erosion.
New, my Acurra plug was under .029 and closer to .027-8 as best as i can measure them.
Hole sizes from .032-.035 do seem to offer the most dependable ignition with a wider variety of primers and flash "channel" sizes.
I have an original Kodiak plug, a OEM Acurra plug and a new in box CVA plug thats a month or two old. The Kodiak/WinApex plug does have MANY more shots through it so it may have some erosion.
New, my Acurra plug was under .029 and closer to .027-8 as best as i can measure them.
Hole sizes from .032-.035 do seem to offer the most dependable ignition with a wider variety of primers and flash "channel" sizes.
GM I will be shooting T7 or APP or JSG. The area I live in you are limited to what you can use in a muzzleloader even in hunting season and I cannot afford to order BH209. I as really wondering what the difference or any advantage of using the larger flashhole compared to the smaller one. I have no way to measure a hole as small as this bp. I did take my set of cutting torch tip cleaners and the new plug hole will accept the 3rd smallest and my Kodiak takes 2 sizes larger if that means anything. I has not been shot but 2-3 times.
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If you are not using BH209 the OEM plug has been just fine for me with Pryodex, T7 loose and pellets...and APP/JSG. All the other subs and real BP ignite just fine with a CVA OEM breach plug. Just keep it clean inside.
Using BH209, some are near 100% and some have had less success. Enlarging the Flash Channel helps carbon buildup from primers. Using cleaner primers like WinT7s or Rem STS work fine with most subs and a stock breach plug.
If i was modding a plug and NOT using BH209, i would probably only enlarge the channel a tiny bit and not the flash hole. Keeping the entire breach plug clean is the key to consistent ignition.
My WinAPex/Kodiak seems the same. The flash HOLE does appear a bit larger than the one in my Acurra, it has almost never had a hang fire but it was dirtier too. I use torch picks also on just the hole. A drill bit or a ProShot shotgun gas port brush works better for keeping the CHANNEL clean.
Using BH209, some are near 100% and some have had less success. Enlarging the Flash Channel helps carbon buildup from primers. Using cleaner primers like WinT7s or Rem STS work fine with most subs and a stock breach plug.
If i was modding a plug and NOT using BH209, i would probably only enlarge the channel a tiny bit and not the flash hole. Keeping the entire breach plug clean is the key to consistent ignition.
My WinAPex/Kodiak seems the same. The flash HOLE does appear a bit larger than the one in my Acurra, it has almost never had a hang fire but it was dirtier too. I use torch picks also on just the hole. A drill bit or a ProShot shotgun gas port brush works better for keeping the CHANNEL clean.
A
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Western Powders will drill your plug to .035 free of charge. Just give them a call. I have surefire ignition with mine now and less fouling in the flash channel.
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smyers717 said:
Ive heard several people mention this and everyone has been a positive response. My only concern is the softer steel they use compared to some. Flame erosion over time could enlarge .035 to near .040 fairly quickly if you shoot the amount i do.
I would prefer to start just a tad smaller depending on the action and primer tolerances.
One of my OEM Knight FPJ plugs is about .037 and IMO that is about the max before blowby gets very extreme.
The typical hunter (only user) would probably never shoot enough to wear it out.
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GM54-120
You've experience now using the CVA plugs with a vent liner. What is your opinion of modifying them plug so they use a vent liner. That does do away with the issue of erosion of the flash hole.
I agree the steel of the CVA plug is some softer than the TC plug.
So, what you think, is going the vent liner route a waste? The factory CVA plug does OK with all powders, if one uses the magnum primers with BH209, doesn't it?
CVA plugs are sorta inexpensive, so perhaps there is really no strong reason to keep them going when the flash hole and/or the primer seat erode, other than it is fun to do so.
You've experience now using the CVA plugs with a vent liner. What is your opinion of modifying them plug so they use a vent liner. That does do away with the issue of erosion of the flash hole.
I agree the steel of the CVA plug is some softer than the TC plug.
So, what you think, is going the vent liner route a waste? The factory CVA plug does OK with all powders, if one uses the magnum primers with BH209, doesn't it?
CVA plugs are sorta inexpensive, so perhaps there is really no strong reason to keep them going when the flash hole and/or the primer seat erode, other than it is fun to do so.
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Adding only a vent liner gives only a small advantage "overall" in a CVA plug. Since there are at least 3 liners on the market with different sizes and shapes. You can also decide "where" in the BP you want the flash hole. Closer or farther from the primer. It can make the plug a bit easier to clean internally too but not to any large degree.
The biggest improvement in any BP for me is the correct primer head space and channel volume. Almost any plug with the right head space will make blowby almost nill and that former blowby must be going somewhere....most likely down the barrel where it belongs.
I still do like the vent liner option though but a OEM CVA plug with a slightly enlarged hole will work the majority of the time for most applications and powders.
The "fun" part is part of the equation too. Just learning how and why, cause and effect is fun for me.
I know one thing for sure, the WinApex has never been so clean as it is now and the Acurra is slightly more dependable with BH209 and plain Win209 primers....those were my goals.
The biggest improvement in any BP for me is the correct primer head space and channel volume. Almost any plug with the right head space will make blowby almost nill and that former blowby must be going somewhere....most likely down the barrel where it belongs.
I still do like the vent liner option though but a OEM CVA plug with a slightly enlarged hole will work the majority of the time for most applications and powders.
The "fun" part is part of the equation too. Just learning how and why, cause and effect is fun for me.
I know one thing for sure, the WinApex has never been so clean as it is now and the Acurra is slightly more dependable with BH209 and plain Win209 primers....those were my goals.
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The origional plug in my Bergara barrel for TC Encore (same plug as Optima and Wolf) had probably 400+ round through it. It was hangfiring with Blackhorn 209 and I always cleaned the carbon from the flash channel after every range trip. I sent that plug to a forum member and had a vent liner installed and the flash channel was enlarged also. I mailed a new plug with 6-8 shots through it to Western Powders to have the flash hole enlarged because it too was hangfiring. Both plugs now have great ignition with regular strength primers but the plug with Lehigh vent liner has alot more blowback. I really do not mind cleaning so in my opinion they are both good. I guess time will tell if the plug drilled out to .035 by Western Powders will enlarge any. The machinist at Western Powders advised he is not sold yet on the vent liners but Don at Western Powders advised me he feels the vent liner is a good design. In my opinion the CVA breech plug needs a 1/8 inch flash channel, like the Knight and Lehigh Plugs, and a flash hole of atleast .032. I just shot the Gen II plug in my GM 54-120 today with regulat CCI primers and it had very little carbon buildup in the flash channel and zero blowback with 9 shots.
It is my opinion that factory CVA plugs do not give spontanious ignition with Blackhorn 209 using Mag primers. I can now shoot with regular strength primers in the two modified plugs with no problems. I am waiting on a trigger kit to come in from Bellms for my Pro Hunter and after I install it I will do more shooting with both plugs.
It is my opinion that factory CVA plugs do not give spontanious ignition with Blackhorn 209 using Mag primers. I can now shoot with regular strength primers in the two modified plugs with no problems. I am waiting on a trigger kit to come in from Bellms for my Pro Hunter and after I install it I will do more shooting with both plugs.
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smyers717
Hopefully you have a caliper, and can measure the over all length of each plug with a primer in the pocket. It is my suspicion the plug with the least blow back has a longer length, and therefore the least head space. Posting what you are able to measure will be instructive to all of us.
Another thing that affects blow back is the 'smoothness' of the primer seat. Flame cutting of the seat results in more and more flame cutting, and more blow back. If you examine the seat, and detect flame cutting, this can be fixed by using a 'C' drill carefully to increase the depth of the primer pocket, and using an o-ring to bring the primer back to the correct height. The over all length can be increased doing this operation which can reduce blow back to zero; zero as in zero.
The enlarged flash hole should enlarge with use. The steel of them plug is not as hard as some. If it gets so opened up that it affects function, it is easily fixed by installing a vent liner.
Repairing both ends of these breech plug is not so very difficult, and actually results in a plug better than 'new' that will last 'forever' because it can be fixed at one end with a new vent liner, and at the other with a new o-ring.
Hopefully you have a caliper, and can measure the over all length of each plug with a primer in the pocket. It is my suspicion the plug with the least blow back has a longer length, and therefore the least head space. Posting what you are able to measure will be instructive to all of us.
Another thing that affects blow back is the 'smoothness' of the primer seat. Flame cutting of the seat results in more and more flame cutting, and more blow back. If you examine the seat, and detect flame cutting, this can be fixed by using a 'C' drill carefully to increase the depth of the primer pocket, and using an o-ring to bring the primer back to the correct height. The over all length can be increased doing this operation which can reduce blow back to zero; zero as in zero.
The enlarged flash hole should enlarge with use. The steel of them plug is not as hard as some. If it gets so opened up that it affects function, it is easily fixed by installing a vent liner.
Repairing both ends of these breech plug is not so very difficult, and actually results in a plug better than 'new' that will last 'forever' because it can be fixed at one end with a new vent liner, and at the other with a new o-ring.
A
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When inserting any primers I have, CCI, CCIM, Federal 209A, Rem STS, and Triple Seven Primers, into the plug then laying a straight edge over the primer all are just under. None will give a crush fit when closing the action. It shoots 1/2 to 3/4 inch groups consistently at 100yds and I should do even better when I get the trigger pull down to around 3lbs next week. My main concern is the gun going "BOOM" when I shoot at a deer and I have accomplished that in both plugs with help from you and Western Powders.
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Ive gotten 3 plugs from Ron and they accomplished what i wanted. Plus i dont need to clean the plug as often during long sessions or with dirtier primers.
Was it a must...no, the OEM worked but could be better. During extended range sessions it is a big improvement in the WinApex with a head spaced breach plug and mid depth vent liner.
That rifle was one of he dirtiest and now its the cleanest of them all. Now i wish i hadnt sold it to my friend.
The Acurra wasnt bad but i prefer standard primers and now they are more dependable plus i can choose the size of the flash hole i want.
During a hunt the larger PR vent liner hole may prove to be an advantage but sofar i have not had a single hangfire with it and the Lehighs. I actually have 2 for this rifle with different liner depths in the plug. One is head spaced and deeper. The other is not head spaced and the liner is close to flush. I havent tried the PR liners in them yet.
Both are as clean or cleaner than the OEM plug with a smaller flash hole. I havent tried a OEM plug with just a enlarged flash hole but IMO it will probably be just fine too.
Was it a must...no, the OEM worked but could be better. During extended range sessions it is a big improvement in the WinApex with a head spaced breach plug and mid depth vent liner.
That rifle was one of he dirtiest and now its the cleanest of them all. Now i wish i hadnt sold it to my friend.
The Acurra wasnt bad but i prefer standard primers and now they are more dependable plus i can choose the size of the flash hole i want.
During a hunt the larger PR vent liner hole may prove to be an advantage but sofar i have not had a single hangfire with it and the Lehighs. I actually have 2 for this rifle with different liner depths in the plug. One is head spaced and deeper. The other is not head spaced and the liner is close to flush. I havent tried the PR liners in them yet.
Both are as clean or cleaner than the OEM plug with a smaller flash hole. I havent tried a OEM plug with just a enlarged flash hole but IMO it will probably be just fine too.
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johnpb said:
Measure the over all length with the primer in the pocket using a caliper. The standard breech plug for my Accura, with a primer installed measures about 1.293". The one installed in my Accura right now measures about 1.307", which reduced headspace by 0.012". This makes for zero blow back. An over all length of 1.318" makes it so my rifle's action won't close.
This may not reveal the 'true' head space of your rifle, but it does reveal what CVA produces to be used in your rifle, and also what will work.
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johnpb
I have done it three ways. All were done because the primer seat was worn because of flame cutting. The factory plugs allowed some little blow back, and that didn't much bother me. However, after the primer seat becomes flame cut, the blow back increases and increases as the flame cutting worsens. I think keeping a rifle cleaner than i do helps keep flame cutting from happening, but i will never know, because i don't have the best habits when it comes to cleanliness.
Busta is the man that fully understands using o-ring to stop blowback. Taking advantage of his knowledge, i used a flattened 'C' drill to deepen the primer pocket of a plug so it could receive an o-ring. This should be done very carefully, so that one can sneak up on the correct depth. If the action won't close on the plug, primer, and p-ring; one drills deeper until the action will close. If this is done carefully, one can end up with reduced head space and zero; zero as in zero blow back. The o ring is compressed some, but not too much, and the seal is made.
Sabotloader made a thread where he used washers instead of o ring, and this reduced head space and therefore blow back. I did this with both stainless steel and aluminum washers. Here the head space was reduced so that there was a slight primer compression when the action is closed. This worked OK for me using the steel washers, but there was a very little blow back. This led me to aluminum washers and a head space that compressed the primer some little. This made for zero blow back and i was thrilled. However, after shot after shot the aluminum eventually failed. This led me to the next and final fix for blow back. I believe GM54-120 still has a couple of plugs in service using this system, and they are working well for him to my knowledge.
The best way to decrease head space for me, was done because i drilled the primer pocket too deep trying to get it to work with the washers. After one drills the primer pocket too deep with the 'C' drill, one might think the only thing left is to toss the breech plug. However, Screwbolts described using a grade 8 bolt as a method to 'heal' the damage. This involves drilling the breech end of the plug with a letter Q drill, and tapping the hole with a 3/8 x 24 tap to receive the grade 8 bolt.
These are pictures of the breech plug for my Omega, and the over all length of the primer and plug ended up being 0.011" longer than a 'new' breech plug. So, the head space is now reduced by 0.011". This results in one being able to 'feel' the primer compress when the action is closed, and this along with a nice smooth primer seat results in zero blow back. Time will tell how long this procedure lasts, but so far so good. The grade 8 bolt is hard and tough like them vent liner are, and they last a very long time on the other end where there is really a lot of heat and flame.
I have done it three ways. All were done because the primer seat was worn because of flame cutting. The factory plugs allowed some little blow back, and that didn't much bother me. However, after the primer seat becomes flame cut, the blow back increases and increases as the flame cutting worsens. I think keeping a rifle cleaner than i do helps keep flame cutting from happening, but i will never know, because i don't have the best habits when it comes to cleanliness.
Busta is the man that fully understands using o-ring to stop blowback. Taking advantage of his knowledge, i used a flattened 'C' drill to deepen the primer pocket of a plug so it could receive an o-ring. This should be done very carefully, so that one can sneak up on the correct depth. If the action won't close on the plug, primer, and p-ring; one drills deeper until the action will close. If this is done carefully, one can end up with reduced head space and zero; zero as in zero blow back. The o ring is compressed some, but not too much, and the seal is made.
Sabotloader made a thread where he used washers instead of o ring, and this reduced head space and therefore blow back. I did this with both stainless steel and aluminum washers. Here the head space was reduced so that there was a slight primer compression when the action is closed. This worked OK for me using the steel washers, but there was a very little blow back. This led me to aluminum washers and a head space that compressed the primer some little. This made for zero blow back and i was thrilled. However, after shot after shot the aluminum eventually failed. This led me to the next and final fix for blow back. I believe GM54-120 still has a couple of plugs in service using this system, and they are working well for him to my knowledge.
The best way to decrease head space for me, was done because i drilled the primer pocket too deep trying to get it to work with the washers. After one drills the primer pocket too deep with the 'C' drill, one might think the only thing left is to toss the breech plug. However, Screwbolts described using a grade 8 bolt as a method to 'heal' the damage. This involves drilling the breech end of the plug with a letter Q drill, and tapping the hole with a 3/8 x 24 tap to receive the grade 8 bolt.
These are pictures of the breech plug for my Omega, and the over all length of the primer and plug ended up being 0.011" longer than a 'new' breech plug. So, the head space is now reduced by 0.011". This results in one being able to 'feel' the primer compress when the action is closed, and this along with a nice smooth primer seat results in zero blow back. Time will tell how long this procedure lasts, but so far so good. The grade 8 bolt is hard and tough like them vent liner are, and they last a very long time on the other end where there is really a lot of heat and flame.
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Yes mine are still working fine. The one in the WinApex is truly amazing compared to the OEM. That was my goal in that rifle. The Acurra was already fairly clean but not 100% with Win209s in all conditions.
Now it is and a bit cleaner.
All the modded plugs achieved MY goals. Your goal/s may be different and thats fine.
Next time im just going to enlarge a OEM flash hole ONLY to .035 and see how it compares.
Thanks again Ron and Sabotloader for all ive learned.
Now it is and a bit cleaner.
All the modded plugs achieved MY goals. Your goal/s may be different and thats fine.
Next time im just going to enlarge a OEM flash hole ONLY to .035 and see how it compares.
Thanks again Ron and Sabotloader for all ive learned.
Could I back out the breachplug on my Accura until, with primer installed, the action just gets to the point of closing completely with no cracks or binding and that be about the same? I tried it yesterday and only shot it once but there was no evidence of any blowback on the scope what so ever. But that has been my 1 and only shot so I do not know how much to expect from the Accura compared to some of my other guns. I'm planning an extended range session around Mon. or Tue. of next week. I found a can of JSG today and will be able to try it and T7. I also have a can of Pryodex RS but I really don't like it. I'll be shooting 240 & 300gr XTPs.
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I shot some APP today. 100gr and a 338gr powerbelt. After one shot i went and got the lead sled :lol:
