Knight KRB7 powder questions

[ShawnT]

Sabotloader,

To those concerned...

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

That is ALL I am shooting. I am trying to just limit the about of blow back to keep the action/triggergroup cleaner.

Hornet22Savage is tring get BH209 to ignite cosistantly and I am just looking to get the action cleaner with T7. Reading his posts and mine is a little confusing since he and I are after different things.

 

[sabotloader]

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.

Se I just do not know enough about the gun.

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

No just the primer... I am trying to see if the pressure created just by the primer is causing the primer to back out of the primer pocket... which again and not knowing a thing about the gun - I think might be happening which would/could cause a delayed fire.

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.

That goes along with what I have been told also... I be,oeve one of Knight's real goals with that gun was to get it as clean as they could.. one way to do that is to reduce the size of the orfice the blow back has to get through. Which leads to another problem with BH - creating a larger flash hole is going to increase blow back.

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 really believe what you have found is exactly why Knigh could not create a fix for the problem. I know they tried different BP concepts, but with out that lock up to maintain pressure with BH - things look grim.

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.

I have and do use the small rifle primer in my Omega with a 25 ACP conversion... while it is great with T7 it is very inconsistent with BH. I have changed the primer to Small Rifle Magnum primer and had real good success, but then you would be approaching the strength of a regular 209 primer. So I would not hold a lot of promise with the Vari - Flame in a KRB with BH.

Also please keep in mind I am not trying to shoot BH209, I am shooting T7 2F. Hornet22Savage is shooting BH209.

Wow! I did not understand that. I thought you both were trying to shoot BH.

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

The w209 is normally the longest regular primer on the market that I know of. Moving to to fatter primer might not help a bit as the fatter primers are the shorter, and the Knight primer pockets are designed wide to get all the different primers in - so shooting a fatter primer would creat a much greater seal. That makes that #5-193 '0' look even more appealing.

This picture shows the common #60 and the #5-193 you can see the difference... amd of course you can go nuts like I did and make a shim from SS washers to INSERT IGNORE to put in the primer pocket + that should help in the amount of blow-back in the breech area.

And in your case the vari-flames might be a legitimate answer as they are longer than w209's

 

[ronlaughlin]

Wow, that's a nice clean picture. Going by the picture, it appears the 25acp conversion is a dream. Going with the variFlame probably is the best way to go, and it may also help with blow back because of the extra length. They do reduce crud ring in my Omega, but they don't eliminate it.

 

[ShawnT]

Sabotloader,

How thick is the #5-193 o-ring, and where did you get them? The smallest the hardware store I went to had was the #60. I did not see it by that number at McMaster Carr either. I cut one of the #60's (.067 thick)in half with a razor knife and it was still too thick, it was .033. I think that (just guessing here) that the Win209 is within .010 of bottoming out and maybe less. I am going to try play with that some more.

And in your case the vari-flames might be a legitimate answer as they are longer than w209's

Do you think that the length would be of help, or would the reduced power of the small rifle primer be of more help? I know you would have to be careful removing the adapter. The way it is now if you pull back quick on the spur for the rolling block it will pretty much pitch the primer out of the action as if it has an ejector.

Se I just do not know enough about the gun

Me too.
I got lucky with a load for deer season, and did not have the time to play with it. Now that the hunting is over I can play around and see if I can make it better.

 

[ShawnT]

Ron,

I thought it might have room for the 25 acp case, not sure if there is enough pressure to worry about the pocket walls being too thin if converted. But a quick look on line showed that the brass is a bit hard to get like you said. Some places did not even list it. The links you sent earlier (actually they are for the same guy) looked like he might have them. I was just a little concerned that the carrier might not INSERT IGNORE them as easy as the primer.

At the moment with W209 primers I did not really have a crud ring with T7 2F. I was actually totally amazed at the lack of one. The action does get dirty though.

 

[sabotloader]

Sabotloader,

How thick is the #5-193 o-ring, and where did you get them? The smallest the hardware store I went to had was the #60. I did not see it by that number at McMaster Carr either. I cut one of the #60's (.067 thick)in half with a razor knife and it was still too thick, it was .033. I think that (just guessing here) that the Win209 is within .010 of bottoming out and maybe less. I am going to try play with that some more.

It measures about 0.050 so it sound to thick also although it has a larger diameter center son the nose of the primer actually pressing down in to the donut hole a bit..

I would think McMaster Carr should certainly have it.. i just did an internet search for 5-193 O ring and came up with some options... might try that.

The other thing PM jsteurrys1 he is a engineer that put me on to them he gets them all the time.

Found them here they are:

http://www1.mscdirect.com/CGI/GSDRVSM?P ... 0167048331

And in your case the vari-flames might be a legitimate answer as they are longer than w209's

Do you think that the length would be of help, or would the reduced power of the small rifle primer be of more help? I know you would have to be careful removing the adapter. The way it is now if you pull back quick on the spur for the rolling block it will pretty much pitch the primer out of the action as if it has an ejector. [/quote]

I do I think they might be exactly the answer but the are hard to come by and as I remember expensive - it is not the best answer just and answer. The best answer is to find the length you need. But without understanding the gun I would not know where to start.

Se I just do not know enough about the gun

Me too.
I got lucky with a load for deer season, and did not have the time to play with it. Now that the hunting is over I can play around and see if I can make it better.

Ron is suggesting the 25 ACP conversion but I am not sure that would work with the primer carrier you describe. Normally you INSERT IGNORE the 25 acp directly into the BP plug, but again without experiance with the KRB - I do not know.

Are you done hunting now?

Another dumb question - with the gun closed and locked up can you get a feeler guage in between the block and the top of the primer?

Another left field thought can you some how measure from the back edge of the receiver to the top of the primer pocket?

If you can install the BP snug and a w209 primer bottomed in the pocket and get that measurement. Then back the BP out a little bit at a time until you get a snug lock up and get that measurement. That would tell you the shim thickness needed.

I still worry about the fact that the block is spring loaded instead of locked - it is always going to back away with blow back on the nose of the primer or even the inside of a 25 acp brass.

I keep going back to the fact that Knight constantly was trying to fight this war and did not come up with a real fix other than squeezing the flash hole.

Wish Idaho were closer to where ever you are.

 

[sabotloader]

Sabotloader,

How thick is the #5-193 o-ring, and where did you get them? The smallest the hardware store I went to had was the #60. I did not see it by that number at McMaster Carr either. I cut one of the #60's (.067 thick)in half with a razor knife and it was still too thick, it was .033. I think that (just guessing here) that the Win209 is within .010 of bottoming out and maybe less. I am going to try play with that some more.

It measures about 0.050 so it sound to thick also although it has a larger diameter center so the nose of the primer actually pressing down into the donut hole a bit..

I would think McMaster Carr should certainly have it.. i just did an internet search for 5-193 O ring and came up with some options... might try that.

The other thing PM jsteurrys1 he is a engineer that put me on to them he gets them all the time.

Found them here they are:

http://www1.mscdirect.com/CGI/GSDRVSM?P ... 0167048331

That was not a good reference - might call them and see what they say - but i would fire a PM to jsterrys1 - tell him I sent you.

And in your case the vari-flames might be a legitimate answer as they are longer than w209's

Do you think that the length would be of help, or would the reduced power of the small rifle primer be of more help? I know you would have to be careful removing the adapter. The way it is now if you pull back quick on the spur for the rolling block it will pretty much pitch the primer out of the action as if it has an ejector. [/quote]

I do I think they might be exactly the answer but the are hard to come by and as I remember expensive - it is not the best answer just and answer. The best answer is to find the length you need. But without understanding the gun I would not know where to start.

Se I just do not know enough about the gun

Me too.
I got lucky with a load for deer season, and did not have the time to play with it. Now that the hunting is over I can play around and see if I can make it better.

Ron is suggesting the 25 ACP conversion but I am not sure that would work with the primer carrier you describe. Normally you INSERT IGNORE the 25 acp directly into the BP plug, but again without experiance with the KRB - I do not know.

Are you done hunting now?

Another dumb question - with the gun closed and locked up can you get a feeler guage in between the block and the top of the primer?

Another left field thought can you some how measure from the back edge of the receiver to the top of the primer pocket?

If you can install the BP snug and a w209 primer bottomed in the pocket and get that measurement. Then back the BP out a little bit at a time until you get a snug lock up and get that measurement. That would tell you the shim thickness needed.

I still worry about the fact that the block is spring loaded instead of locked - it is always going to back away with blow back on the nose of the primer or even the inside of a 25 acp brass.

I keep going back to the fact that Knight constantly was trying to fight this war and did not come up with a real fix other than squeezing the flash hole.

Wish Idaho were closer to where ever you are.[/quote]

 

[ShawnT]

Sabotloader,

The end of the block sort of recesses into the action frame so there is no way to get a feeler guage in. If you remove ther trigger group to get at it you are also removing the hammer and block too, it is all one assembly. you can do the feeler guage thing on it with the assembly ion your hand but then the breech plug is not in the picture.

I did fire some primers this morning to see if you can actually see the block move back when fired. I cannot see it move back any, but do see it move forward at the strike of the hammer. I think that is just the hammer seating the primer, but you still get a quite a bit of soot on the primer and in the action. I did fire one after closing the block and then pushing harder on the block to try to manually seat the primer. Still dirty but did not really see the block move when fired. The CCIM (worst)and Fed (little better) are the dirtiest and Win is a little better. What I do see is that you get more soot on one side of the primer cup. That would seem to indicate that the primer is not fully seated all the way around or is slightly cocked.

Is the #5-193 oring the same OD as the #60? I don't think it is going to fit as is either but the idea of the primer seating down into the oring is interesting.

As for the 25ACP case, It could work, but you would have to open the notch in the carrier a little to get the case in. I was thinking that where you would possible have a little trouble is getting the mouth of the case to enter the plug smoothly. The rounded end of the primer goes in pretty smooth. But it is still posssible. Another thought would be to remove the carrier and just INSERT IGNORE the 25ACP case manually then close the block on it.

But as we both know none of that gets past the spring holding the block closed. So it may just be a loosing battle, but it is fun to try to figure out if something can be done. I did not get to talk much to Sam about it, but I had read that they did not really come up with anything either.

Yea hunting is all done this year. I got skunked. First time in many years. But that is hunting. Saw several doe and one very small buck, but they always seemed to be on the opposite site of the property out of range. We are bordered on 2 sides by paper company land and they cut our side of the road last year. Last year they were actually cutting during season and that moved them around. This year the deer patterns are just all screwed up.

 

[Busta]

ShawnT,

Another way to figure out your headspace,,, is to measure the length of a Winchester 209 primer,,,then INSERT IGNORE it into your breech plug,,,fire it then remeasure the length. It might not come out perfect in your rolling block, but works fairly well in a standing breech.

What happens is the primer cup will slide back in the battery cup. The difference in length before and after will be very close to how much wiggle room (extra headspace) you have, AS LONG as the primer holder is not holding the battery cup from making contact with the bottom off the primer pocket.

The block arangement in the KRB7 does not lend itself to anything precise, but that should get you real close.

You could try this o-ring, it is a metric ring that measures 4.5mm ID, 6.5mm OD, and 1mm thick (0.0395" to 0.040" thick).

Part # 9262K611
http://www.mcmaster.com/#9262k611/=aayqsp

 

[sabotloader]

Busta

Thanks Busta... good information my meager memory bank also...

 

[ShawnT]

Busta,

I measured a couple of the primers that I have fired off this morning. They were .301-.302 to start and wound up .305-.306, but they have a lot of soot and debris on the end.

I spent some time this afternoon adding some transparent tape to the end of an unfired primer, just the end that seats in the bottom of the plugs pocket. The tape is .002 thick. I started with 2 peices on a .300 W209 primer, so it was .304. I then applied a small amount of prussin blue and inserted the primer and let the block position it. I saw no transfer of the blue until I got to .307 in length, but better transfer at .308, and I also added a little touch of the blue to the back of the flange and it was transferring to the block face. So it looks like I have around .007-.008 free space infront of the primer. At that point it looked like the block was just ever so slightly pushed back (open), but It fired off ok. When I fired it the tape burned away, but the primer was cleaner and was at .305 in length. Looks Like the Vari-Flame may worth a try.

 

[Hornet22savage]

I have tried the #5-193 O-Ring in my plug it does not allow the block to close far enough for the hammer to hit the firing pin.

 

[ronlaughlin]

ShawnT

One thing that i wonder when i read these posts is, if you tried the o-ring suggested by Busta, and used STS primer, would this work in your rifle. Normally them o-ring compress some, when a rifle is put into battery. Perhaps your rifle doesn't have the ability to give a slight compression to the o-ring, or perhaps it does.

I believe it is possible the metric o-ring would work in my rifles, without making the primer pocket deeper, but certainly don't know for sure.

 

[Busta]

Busta,

I measured a couple of the primers that I have fired off this morning. They were .301-.302 to start and wound up .305-.306, but they have a lot of soot and debris on the end.

I spent some time this afternoon adding some transparent tape to the end of an unfired primer, just the end that seats in the bottom of the plugs pocket. The tape is .002 thick. I started with 2 peices on a .300 W209 primer, so it was .304. I then applied a small amount of prussin blue and inserted the primer and let the block position it. I saw no transfer of the blue until I got to .307 in length, but better transfer at .308, and I also added a little touch of the blue to the back of the flange and it was transferring to the block face. So it looks like I have around .007-.008 free space infront of the primer. At that point it looked like the block was just ever so slightly pushed back (open), but It fired off ok. When I fired it the tape burned away, but the primer was cleaner and was at .305 in length. Looks Like the Vari-Flame may worth a try.

ShawnT,

It sounds as if your primer holder may be holding your primer from seating into the bottom of the primer pocket? This will prevent you from getting an accurate overall measurement of your fired primer, AND is probably the main reason of your blowback.

Like Ron mentioned, by trying a Remington STS primer with the 1mm thick o-ring, you might have enough room to lock up your block. The Remington STS primer is shorter than most others, and the front of the primer has a more rounded face. This would mean that there would be more room for the o-ring in the bottom of the primer pocket, as the contact would be somewhat past the front of the primer.

If you PM me your address, some 1mm thick o-rings will show up in the mail a few days later. Then try some shorter primers until you can lock up the block with the o-ring in place.

 

[ShawnT]

Busta,

Pm sent. I would love to try the o-ring you suggest. The primers may be the hardest for me to find, but I will start makeing some phone calls Monday.

Busta and Ron,

I am not sure the primer carrier is actually holding it from seating fully, but that is possible. Earlier in the day I had also applied a bit of the prussin blue to the end of the breech plug and it did transfer to the back of that carrier so it appears that the carrier is at least very close to the BP. But I did not get transfer of the blue to the face of the block until adding the tape to the primer to shim it back. So it is possible that the carrier is keeping it from fully seating, but if the carrier were removed I don't think the block would close down on the primer enough to seat the primer. The down side here is the spring for the block. While it seems to hold the block forward good, I suspect that it is rocking a bit under fire. If you take the trigger group out of the rifle and hold it so you can see, you will see that you can pull back on it a little (compressing the spring) without "unlocking" the ball detent from its notch on the bottom of the block. So I think I might have to increase the tension there also.

 

[ShawnT]

I did a little more looking at the Block and carrier on the trigger group. I found that the carrier was not held back to the block when it was closed and it was looser one one side more than the other. I removed the carrier pin and then the block. I fashioned a new spring from some Brownells spring stock that I had. The original spring is made from .030 wire and was about .308 long. The stock I used was .035 and I made it about .490 long. It did tighten up the lock up, but you can still pull back on it some before it unlocks. There would not be anyway to over come that. I do not have any wire stock that is heavier and will still fit into the recess for it. I made it about as long as you can and still have it function without binding on the spring as it compresses when you open the block. After that I put the carrier back on and turned the Slotted spring pin so that the slot is to the rear of the carrier (closest to the block) the used a center punch to flare the open ends of the slotted spring pin to "tighten" up the carrier to the block. Now it sits back agains the block when closed but still functions smoothly. I will try to INSERT IGNORE the o-ring Busta is suggesting and get some of the Rem STS primers that he and Ron suggest and see if this combination will add up to something.

 

[ShawnT]

I got some different o-rings in the mail today from jsteurrys and Busta, thanks again guys. I tried one that was thinner and had a larger id (they both sent the same one) with a Rem STS primer, I was able to find some. This oring is just right on the od, and the id is large enough to match up with the flame channel opening.

Here is what I found.

If I let the block forward normally it will not go forward far enough to fire. If I press hard on the block, it seems to move in a bit more and will then fire the primer. So I am real close. I am not sure but think If I had the original block spring in the trigger group it might not hold it closed that last little bit. I did some more checking and found the following. Without a primer the block closes so that there is .007, using feeler guages, between the frame and the top of the block face. With an STS primer, and NO o-ring it is .010. With o-ring and STS primer it is .043. With the o-ring and pressing hard I was able to fire 3 primers ok and they were VERY CLEAN! 8)

Another thing I noticed was it looks like the block is open just far enough that it might have allowed the post on the hammer saftey to rub the opening in the block for the firing pin. The top of the post (part that strikes the firing pin) of the hammer saftey is shinny from rubbing the opening for the firing pin and that opening has a small notch forming in it. This could just be from cocking the hammer too, or from trying to fire with the larger o-rings. I think if the pocket was made about .020 deeper, I would be golden. Plus I would not have to worry about the o-ring not "pushing" the block back again and preventing it from firing. So I am going to see if I can make up a letter C drill to do that (I saw somewhere someone did that on this forum but don't remember exactly who) and still leave me a fairly flat bottom in the pocket of the BP. I am not sure I can regrind the bit since I do not have a real bench grinder but I may still see if can do it with a disc grinder. After that I will need to see if the Rem STS changes my groups any.

ShawnT

 

[ShawnT]

Today I picked up a letter C Drill bit and reground the cutting end to a very shallow angle to give as flat a bottom as possible. I found it was ronlaughlin that had posted pics of doing this. I also broke out a spare breech plug that I had ordered. I found that the spare plug was a little shorter in length. I decvided to use this plug for modifying since I know that the original plug gives me great groups. I used the modified drill bit to deepen the primer pocket .013, this just happened to be where I stopped on the first try and then tried it in the rifle. With the other tolerences of the plug being shorter I found that I can now fire the Rem STS and W209 primers. I think I can go about another .008 and still be good, and still may do that. I plan to take the rifle to the range and shoot it as soon as time permits. I never took pictures of the dirty primers, you all have seen those. The action was clean and had no smoke from it like I did before. The O-Ring has had 10 primers fired on it and still looks new.

Here is the primers I fired today and the bit used to deepen the pocket.

 

[ronlaughlin]

Nice job grinding that drill! At that depth, i assume you are using the metric o-ring? Seems the 1/16" o-ring would be too thick at that depth. Seems to me, in order to use the 1/16" o-ring you would have to make the bottom of the primer pocket some 0.030" deeper at least. Keep up the good work; it is nice to win once in a while.

 

[Busta]

Shawn,

Looks good so far. Let us know how it goes at the range. Do you know how much compression you have now on the o-ring? If I were you, I would do some shooting with both the longer Winchester W209, and the shorter Remington STS before making any other changes at this point. As long as your block is in position and your hammer is dropping fine?