Knight KRB7 powder questions

[ShawnT]

Saboloader, JStanley,

Thanks. I am a little suprised at the variations. I would not have expected .008 in variation. .002 or .003 maybe but that seems like quite a bit.

I just got my trigger group back last night from Sam. He replaced the entire hammer asssembly (hammer and hammer saftey). I was not able to spend too much time looking at it, but it did fix the original problem in that it will now strike the firing pin with a spur on it. I can tell you that with the rolling block in the forward (fire) position you can still slightly pull back on the block and see it press down on the spring a little, and still not move the ball out of the detent pocket, so there is a fair amount of slop there. This is what could happen when the pressure builds under fire. I was sort of wondering if that variflame would compensate for that by bottoming out in the primer pocket of the plug and pushing the block back just a bit. I also need to look at the bracket that holds the primer too, it is possible that it does not hold the primer tight to the face of the rolling block. I hope to study it some this weekend. If I get some time and get a little ambitious, I might see if I can replace that spring for a heavier one. But if the ball is on the small side for the pocket then I don't think the spring will help much, same with the position of the primer bracket.

 

[JStanley]

Shawn -

I don't believe the variation is in the product itself. I measured several of my adapters and found them all to be within .001 of each other. The big difference comes when you measure one with a primer installed. The tool they supply to INSERT IGNORE them relies on you smacking a plastic plunger with the butt/palm of your hand. It's not difficult but it isn't precise either! Good news though, when you INSERT IGNORE the primer in the BP and close it up, any slight differences (.001-.008) are corrected as the face of the action presses against the primer & BP. I did a little test. I seated some less than completely and then loaded them into my Omega and closed the action. I could make a poorly seated primer (.318) instantly go back to the completely seated length of approx. .308 (an empty adaptor). The adaptors are machined out of brass and are really a good product that all my ML's love-especially the closed breech ones. They are VERY clean shooters in my Omega.

Sabotloader - does this line up with your experiences?

Be blessed.

 

[ShawnT]

JStanley,

Ok that makes more sense to me. I thought you were just measuring the adapter itself. I can see that the tolerences will go up as you add the variations in primer length and seating.

Sabotloader,

Did you measure yours with a primer, or just the adapter?

 

[sabotloader]

ShawnT

With primers inserted - althought I use a Lee primer tool to INSERT IGNORE my primers...

Let me measure real quickly again.

Yep! the primers are just above the rim so that is with primers installed...

 

[ShawnT]

Thanks guys. Is PR the only place that has the adapters? I thought Cabelas had them at one time but don't remember seeing them in the catalog for some time.

 

[JStanley]

I bought mine at the Cabela's in Minneapolis. (traveling for work)

 

[GM54-120]

Mine had a couple sets last time i was there.

 

[ShawnT]

Cabela's do not show them online or in any of the current catalogs. Must have dropped them.

 

[ronlaughlin]

Cabela's do not show them online or in any of the current catalogs. Must have dropped them.

http://www.blackpowderbullets.com/varif ... apter.html


http://muzzleloadingbullets.com/varifla ... apter.html


They seem available at these stores, plus Precision Rifle still shows them on it's website. If you order, i recommend you purchase extra adapters.

Another, perhaps more better, solution would be to convert your breech plug to use 25acp brass as a primer holder. I have never seen the breech plug from your rifle, so it may be it isn't possible to make this conversion. Also, some say the 25 brass are too hard to find, and recommend the 32acp conversion. A picture of your breech plug may reveal if either of these conversion are possible. Contact me, if you desire help.

 

[ShawnT]

Ron,

Here are a couple pics of the BP for the KRB7. I am not sure that the ACP conversion would work as well but it might, just thinking of how well the assembly would inset the brass. I am not really looking at this to get BH209 to work, just more interested in reducing blow back with T7. The OD of the plug at the primer pocket is .374 and the id is about .243 so it would need to be opened up to about .280 to accept the acp brass. My Sierra manual says the acp brass is .278 in diameter so I figure at minimum you would need about .002 allowing .001 on each side of the brass and .003 may be better. That would leave about .047 (.094/2=.047 per side) for the bp wall thickness at the primer pocket. with variations on brass it might need a bit more. Then you have the primer holder infront of the rolling block too. The opening in it is about .265 so it would require some modification. and if you open it up and the ACP don't work favorably you might have to replace it to go back. You also only have a spring to keep them locked up. With the block in the forward position you can pull them back a little without unlocking it since it is just compressing the spring. I am thinking a heavier spring inder the ball detent will help that.

These are Domed plugs too.

Front of trigger group.

 

[Hornet22savage]

Since there is a lot of dicussion on this topic I contacted Western Powders on this matter and here is the response I got from Keith.

Clifford,

Thank you for your interest in Western Powders, Inc. "Blackhorn 209" black powder substitute.

We have had some luck with getting the KRB7 to work and you are on the right track. With the Lehigh bullets vent liner you need to recess the front of the breech plug so that the flash hole is approximately .700" from the bottom of the primer pocket. You will have to recess the front of the breech plug a considerable amount to achieve this. Even with this modification you should stick with either the CCI 209M or Federal 209A primer. This has to do with the fact that these primers have a tougher primer cup and are not as likely to separate. In a lot of the KRB7 muzzle loaders, the rolling block does not seal tightly against the breech of the barrel and we have seen the primer separate form the primer cup and blow out of the back of the gun in the gap between the breech block and the barrel. This was with Winchester primers but we have never had a problem with the recommended primers.

Did you use pin gauges to check the flash hole diameter of the vent liner. I've never seen any Lehigh vent liners with that large of a flash hole. Dave Fricke from Lehigh bullets normally keeps the flash hole in the .030" range. Since the vent liners are hardened you would need to purchase a vent liner with a proper sized flash hole for BH 209 use directly from Lehigh bullets.

I hope this answers your questions.

Best regards,

Best regards,
Keith Anderson
Western Powders Ballistic Lab

 

[sabotloader]

Hornet22savage

I can tell you right now the further you recess the vent liner in the plug the greater the blow back pressure will be against the face of the primer. The block of the KRB will not be able to handle the pressure.

Western's stock answer to getting BH to ignite is to move the powder closer to the face of the primer and they are certainly correct about that. They really want it to be like a shell with the powder against the primer. But in that they do not account for blow back pressure against the primer. Their primary concern is ignition.

IMO they also fail to recognize the importance of the flash channel having the properties to handle the pressures from the intense primer that they recommend.

In my modified breech plugs - I can shoot BH with Win T7 primers all day even with the old Remington 209-4 primer built for the 410 shotgun, and of course with that I do not build up the carbon to clog the flas channel.

 

[Hornet22savage]

I understand that the further you recess the plug the more blow back you will get. However if you have owned or shot a KRB you know that they are a dirty action anyway. I just want to be able to use BH 209, it does not matter what powder I use it will still take me a while to clean the trigger group. From what I have right now I have a half to one second delay with Mag primers, all the test shots i have taken so far my primers have come out cleaner than with T7. Understand that I'm not going to go out and follow their recomendations right away. I have a process and will follow that process, if the end result is what they said then so be it. I already have to spend a good amount of time cleaning after a day of shooting, I hate to spend even more time cleaning between shots. I will post more as I go and hope that it will help others. I think sometimes people get caught up on making a gun as clean as it can be and lose sight of the fact that some guns are just dirty, the KRB is one of them, without putting a lock on the block to keep in place there is no way to prevent it from recoiling a little bit and losing seal, however it is not going to open far enough to let anything other than gas escape. The primer is trapped between the firing pin and primer carrier.

 

[sabotloader]

I understand that the further you recess the plug the more blow back you will get. However if you have owned or shot a KRB you know that they are a dirty action anyway. I just want to be able to use BH 209, it does not matter what powder I use it will still take me a while to clean the trigger group.

I can understand that but from what I have been told because i do not have one the block is a spring action block. Bringing the powder closer to the primer is going to increase the the pressure on that block pushing it open quicker and harder dropping the pressure quickly, possibly also resulting in a hang fire.

From what I have right now I have a half to one second delay with Mag primers, all the test shots i have taken so far my primers have come out cleaner than with T7. Understand that I'm not going to go out and follow their recomendations right away.

This is exactly what I found in other guns and I truly believe part of that problem is trying to get all of that pressure and debris down the flash channel to the flash hole. A case in point - one of the rifles I shoot is a Remington 700ml. It goes against all of the rules established by Western... open breech - open nipple - flash hole that is to small. With all of these problems if I shoot a Mag primer the gun may ar may not go off with BH. But if I back down to a milder primer such as a Remington SST or even a Cheddite - the gun shoots BH great - no hang fires - shot after shot. The difference... the flash channel is so narrow in the Remington nipple if I use a Mag Primer the pressure and debris clogs the channel and delays ignition until the pressure reduces enough to let the heat move through.

I am not very good explaining things in words so the other day i wrote this simple analylogy...

Think if it this way... go find two straws a fairly skinny straw and a larger one like for milk shakes.... Fill you mouth and cheeks with water... place the straw in your mouth and bow the water out of the straws.... Which straw more effeciently empties the water in your mouth? Now imagine instead of water you were blowing heat and pressure - which opening would get more heat and pressure to the flash hole.... Next step what if you opened the flash hole a couple of thousands - ????? See what I am working to.

The plug that has been posted of a KRB breech plug appears to be about the same thing that I use in a DISC series gun. I have modfied them to allow a better breathing flame channel and the insertion of a Lehigh Vent liner on the end of the plug. With the modified plug I routinely shoot BH with a W209 primer. I do remember that when the KRB was developed Knight closed the flash hole down as small as they could hoping to keep the mess in the breech as minimal as possible.

I have a process and will follow that process, if the end result is what they said then so be it. I already have to spend a good amount of time cleaning after a day of shooting, I hate to spend even more time cleaning between shots. I will post more as I go and hope that it will help others. I think sometimes people get caught up on making a gun as clean as it can be and lose sight of the fact that some guns are just dirty, the KRB is one of them, without putting a lock on the block to keep in place there is no way to prevent it from recoiling a little bit and losing seal, however it is not going to open far enough to let anything other than gas escape. The primer is trapped between the firing pin and primer carrier.

I do want you know that I am not questioning your process. You certainly can proceed on you chosen route. I simply wanted to suggest to you the longer the flash channel the less blow back pressure you will feel on the face of the primer - therefore less push on the block - whether it is less enough i have no idea...

Also want you know that I am open and willing to do a plug modification for you... even just for my own information.

This picture kinda explains what I do...

If you have not read through this thread - you might spend a few minutes over there.

http://www.modernmuzzleloader.com/phpBB ... sc&start=0

And again I have no ideal in the world if this will/would help a KRB - but i would like to find out...

 

[ShawnT]

Sabotloader,

I was just looking at the drawing you posted. I had done a little measuring today. The Flash Channel in the plugs I have is in the neighborhood of .166-.167. I can put a #19 drill in with only a slight amount of freeplay but a #18, .168, will not go. The one measurement I have not figured out yet is how much free play there is between the bottom of the primer cup and the bottom of the primer pocket. But when I applied a little prussin blue to the primer cup I got a very slight amount on the bottom of the pocket. It was not full contact and looked like it was just from a little thicker amount of blue from on the primer. So it looks close. I went to the hardware store and got a couple of #60 o-rings out of curiosity. You cannot close the rolling block with one inserted into the pocket. I then cut one in half (thickness) and tried again, but it would still not close all the way. So it must be close. A little prussin blue on the BP transfers to the primer carrier to they must touch.

Hornet22Savage,

I got a couple of questions for you?

Have you tried the Vari-Flame adapter for Small Rifle primers in your KRB?

Do you Grease or Tape your breech plug?

When shooting T7 did you still have a dirty bore and crud ring or just have the real dirty primers and action?

I have used both CCI's, Federal 209a and Win209 primers and they were all dirty. The action does get dirty but I have went to spray cleaning the trigger group due to the amount of soot that gets on/in it. I have a pretty clean bore with no crud ring to speak of so I am just looking to limit the amount of blow back. I was planning to see if I could change the spring for the Block, I have some spring stock from Brownells, but found that you cannot just take the block out, you have to remove the hammer first. I plan to try tying up the spring for the hammer tomorrow so I can get it all apart, it has a pretty heavy spring. I am just curious to see if I can get some more tension on the block.

I was just using grease on the plug but I am going to try taping it like Sabotloader does.

 

[Hornet22savage]

After reading the thread you posted, it has become aparent to me that there are several ways to make a plug fire BH209. My plug has been modified with a flash channel that is larger than 5/32 and a ventliner. With Win 209 primers blue box I have a terrible hang fire. It's more of a bang swoosh. With CCI 209M primers I get a Bang Boom better ignition. So my thought were to have my dad who is a machinest open up ther ventliner to .035 and try that to see it it elimanates my delay, if not deepen the powder pocket in small increments until I elimanate the delay. If I get a chance I will take some shots and post pictures of the primers as is to show how clean they are, before any more mods are done.

 

[Anonymous]

If you find some Remington STS primers give them a try. I use them a lot to ignite BH209 in my guns. To me they seem to be a "fatter primer" then others.

 

[sabotloader]

ShawnT

The Flash Channel in the plugs I have is in the neighborhood of .166-.167. I can put a #19 drill in with only a slight amount of freeplay but a #18, .168, will not go.

I did not know that the flash channel was that large. I did no that Knight was opening them. but because of the success they had with the Vison plug that may have spurred that move.

Next then would be what is the diameter of the flash hole. If I remember right when I was first reading about them it was .028/.029? What ever it might be I think the design shape of the Lehigh vent liner would add the ability of the rifle to ignite BH...

Dang i wish I had a KRB to work with.... but such is life.

You have probably already done this but if you get a chance INSERT IGNORE a Mag primer in the pocket. Lock up the block on the primer. Is there any forward/backward movement of the block at lock up?

Then if you can shoot a mag primer while observing the block from the side, does the block move back any with the discharge of the primer or with your finger on the block can you feel it recoil any (if you can do this safetly)?

Next use a w209 primer and see if the results are the same?

The one measurement I have not figured out yet is how much free play there is between the bottom of the primer cup and the bottom of the primer pocket.

To get this measurement... remove the breech plug from the gun and measure the length of the plug from the top of the primer pocket to the flange on the face of the breech plug that touches the flange in the barrel. The one that I have that looks like yours measures 1.594"

Next INSERT IGNORE a bare primer in the the primer pocket. Even if you have to tap the top a bit seat the primer in the bottom of the pocket with the nose of the primer on the primer shelf inside the BP.

When I install a Fed 209A in the pocket the length measurement increases to 1.724"

Reinstall the breech plug in the the gun snug up against the stop in the barrel.

Carefully wrap a piece of teflon around the primer to increase it's diameter so that it will not go down in the pocket easily. INSERT IGNORE it into the primer pocket and close the block. The block should push the primer in as deep as the block needs it to go. Then carefully open the block and hopefully the primer will stay in place, remove the BP with a deep socket, again trying not to move the primer, then measure the length of the BP with primer this should give the desired length of your gun. Subtract your two measurements and you should have the roughly the head space needed.

Another "o" ring that might work better for you is a #5-193. This is a comercial "o" ring that you would have to get from a auto parts store or a fasteners store someplace that handles commercial parts.

The final thing is not good - but from everything I have read the real problem lies in the lock up block. The block does not retain enough pressure to force the the bulk of the pop from the primer to get to and through the flash hole. If that is truely the case then moving the powder down to the primer might be the only way to get it to go off, but even then I fear that you will get inconsistent results. Because if you get it ignited the back pressure will push the primer back and release the pressure causing the powder a real delayed ignition or even misfire.

I actually have a set of Vari-flame adapters that I will never use - I can push the primers out and send them to you if you want. Do not think think they are going to solve your problem but you are welcome to them.

Another thing - I know Knight tried several things to get the KRB to be comaptible with BH - they never did come up with a viable solution. Perhaps one of the reasons the KRB was dropped.

 

[sabotloader]

To those concerned...

A dumb question... does any of these problems occur when shooting T7?

 

[ShawnT]

Sabotloader,

While the way you got your measurement will work with the others I can't see it working with the KRB. Look at the last picture I posted. The primer sits in the carrier (notched on the block side for the primer flange) in front of the block and the carrier is Pinned to the block. Any rearward movement of the block pulls the primer back. So in order to do your measurements the carrier would have to be removed, then inset the primer into the plug by fingers and move the block forward. That might work but will be a lot more work since the hammer has to be removed to get the block off with the carrier attached. But it might be possible to punch the pin out for the carrier first. I'll look at that more tomorrow.

Do you mean Fire a load with each primer or just fire the primer?

The Flash hole in the (OEM) plug appears to be tapered too. From the powder side I can get the tip of a torch tip cleaner in that is .032, but only part way, not all the way into the channel. The size that will fit and protrude into the channel is .027.

I don't see anyway to really hold a tight seal with the rolling block due to the spring that holds it in place either. With the assembly in your hand, so you can see, you can pull back on the block and see it compress the spring a bit yet still not unlock the detent ball from it's notch. I was pondering a heavier spring to possibly overcome some of that, but don't see it will in anyway arest any rearward movement when the pressure builds up.

I was contemplating the Vari-flame adapter when you and JStanley mentioned them and they appear to be slightly longer than a standard primer. But then again if the pressure is what is unseating the primer due to the spring lockup, even that might not help. If the Vari-flame did End/lessen the blow back, then it may be more due to the reduced pressure of the small rifle primer over the 209. Also please keep in mind I am not trying to shoot BH209, I am shooting T7 2F. Hornet22Savage is shooting BH209.

At the moment the W209 is the primer I had that this rifle really liked. I have not seen anyone locally that caries the Rem STS or Cheddite. Mostly CCI and Fed around here. I do recall trying the Fed and CCI Mag on several shots, trying to see if they affected the groups, and then all of the sudden I had no fires. Turned out that the debris had caused the firing pin to hang up. Washed that part of the block out and it was fireing again. I did not have that problem using the win209.not