Key-holing Bullets, again.

[Jellymon]

I bought my knight disk extreme (western setup with musket caps) about 7 or so years ago. The first few seasons it shot very well with the German musket caps, 100g of FF T7 with 300g bloodlines and 240g xtp. Usually 2”, sometimes 3” groups.

A couple years ago I started seeing a random shot slightly key hole with the 300g bloodlines so I posted a thread here and got advice to up my powder charge. So I went to 115g of T7 and it seemed to help, even though the groups had opened up a little.

Last week I went out to verify my zero and practice for the upcoming season and try out some barnes 290g spitfire t-ez’s. So I set up at 50yds and my groups are 8-10" with Bullets hitting sideways and other variations of keyholing. Thinking my gun just doesn’t like those Bullets I tried out my bloodlines and XTP’s, same thing, Bullets hitting sideways, and keyholing at 50!

So, the ff triple 7 was from last year, so thinking i had bad powder I went and bought some new fff triple7 thinking the extra velocity would help me. Nope, same results. So I looked at the bottle and noticed it says 100g max for a 250 and 300g bullet. So I tried 95g and the bloodlines grouped 3” at 100yds with only one hole very slightly keyholed. The Barnes spitfires still didn’t group very well at 50 and one keyholed. I ran out of light to test ferther.

So far the lighter powder charge seems to be helping, I’m going to need to test more. So any input? Am I on the right track using a lighter charge, or am I missing something? The barrel looks to be in very good condition and the crown looks perfect. Probably has 300+ rounds through it. Anything is appreciated, sorry for so much info. Very frustrating since this gun was so accurate and reliable for so long and the cause of many dirt naps. Pics to come.

[Jellymon]

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[Jellymon]

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[jbeaumont21]

My buddy went through the same thing with his Knight Disc Extreme that he bought about 6-7 years ago.  Finally sent it into Knight and they sent him a new rifle.  They must have made a few bad batches during that time 

[Jellymon]

My buddy went through the same thing with his Knight Disc Extreme that he bought about 6-7 years ago.  Finally sent it into Knight and they sent him a new rifle.  They must have made a few bad batches during that time 

That’s what I’m afraid of...

[jbeaumont21]

I found his post on it from back in 2013 which means he must have bought it in 2012. That makes it 7 years old so could be from the same batch.  On the brighter side you should get a new gun out of the deal.  I'm pretty sure he sent his in just a couple years ago and he got a new gun in place of it.

https://hunting-washington.com/smf/index.php/topic,128763.msg1716477.html#msg1716477

[Jellymon]

Just looked. Bought mine in 2012 as well.

[MountainDevil54]

is it a  1:30 twist? Could be that it doesnt stabilize those longer bullets.

[Jellymon]

is it a  1:30 twist? Could be that it doesnt stabilize those longer bullets.

It’s a 1:28 twist. I’m having the short 240g xtp keyhole as well. The first few years I had it it shot very well. But it’s gotten progressively worse the last few years.
I’m going to test one more time letting the barrel cool between shots like what I read in the link JB posted above, and if I get the same thing I’m contacting Knight. This gun should easily shoot with the loads I’m feeding it.

[Jellymon]

This is how it shot 100g of ff T7 and 300g bloodlines when i first got it. The tight group is 3 shots at 100yds open sights. Obviously though the other pic is more of an average of what it shot in the past.

[Sabotloader]

Jellymon

I am not totally sure what might be the problem with you rifle, but after reading your last post where you indicate at one time it shot well but now isn't - I do wonder about the bore itself.

Tumbling usually occurs when the sabot bullet combination does not get to the revolution speed (spin) it need to stabilize the bullet.  In my thoughts two things possibly a third may be happening

1. the bullet is slipping in the sabot and not turning with the sabot.  Again in my mind there is only a very remote chance this is happening since the 458-300 has distinctive knurls on the bullet to catch/latch into the sabot.

2. Somehow the sabot is slipping up the bore and not catching the lands of the bore to achieve the correct spin rate. I believe this to be the more probable answer.

There may be a real possibility that material (burned powder - even some plastic fouling which is very rare anymore) has built up on the back side of the lands and the sabot is unable to grasp the lands.  Since I do not know you your cleaning routine that is only a guess.

Also before you shoot do you remove as much oil or cleaning materials as you can before loading those first shots.  Do you shoot a few caps or primers before loading and shooting.

My first guess is really the bore needs to be thoroughly cleaned with an aggressive product like Barnes CR-10, Montana Extreme Bore Solvent, or some such product.  When applying these products they need to sit in the bore for 10-15 minutes and allowed to dissolve materials out of the bore.  Then use a good fiber brush to help dislodge the dissolved materials.
 
3. You actually do have a problem with the bore itself - not impossible at all but far down on my list of checks

Have you looked at your bore with a bore light or removal of the BP and look through bore at a light? Do the lands stand out in the bore from top to bottom.

Next when you are pushing your sabot/bullet combination down the bore, and after it passes through the crown, does it go down the bore with the same pressure top bottom.  No place along the bore that it seems to get larger and is far easier to push the load down?

Just some suggestions as to where I would start.

[Jellymon]

Thanks for the reply. Yes looking through the bore with a light the lands stand out and the bore looks shiny when clean. When clean, the first loading feels like it takes consistent pressure all the way down. Same thing after swabbing the bore between shots. If I don’t swab between shots, the first few inches are very hard to load, the middle gets easy, then towards the breech gets hard again, and there is a noticeable “white” residue in the last few inches of the bore that looks like it fills the grooves. No I don’t do anything to the clean barrel before firing my first shots.

I start cleaning with a  wet patch of TC #13 bore cleaner. 2-3 patches of that before the patches start to come out clean. Then I use a brass brush for 5 passes, followed by 2-3 more patches with the TC #13 which usually are coming out clean at this point. Then I put a few dry patches through until dry. I usually do this every 6-9 shots.

[Jellymon]

Looking closer I see some of the white residue (plastic?) in streaks going straight through the bore not following the rifling. Not sure if it’s from cleaning or not. Before shooting again I’m going to a more thorough cleaning. Thanks for the help. 

[Sabotloader]

Of course I really can tell - but looking at the pics It really looks like the grooves are coated with something.  So doing a bore cleaning with a good bore cleaning solvent might really do something for you.  Remember to give the bore solvent time to work in the barrel before patching it out. Actually you may need to do a treatment 2 or 3 times.

Those really are good pics of the muzzle you posted.

This is the type of bore brush I use - it is not a metal brush.  Just thinking you might need a brush at this point. Normally I do not use one in the bore.



A couple of additional pics....

Once you get the bore clean this is my quick and easy way to maintain it.  But, again make sure you give the 2-n-1 bore cleaner time to work. 



The 2-n-1 Bore cleaner shown here probably is not strong enough to get you need done now, it is more or less maintenance for me.

One more pic showing how I make the Windex Patches



The Ammonia in Blue Windex - is a natural metal stripper. There is not a lot of Ammonia in the in Windex but it really dissolves powder residue. 

[Jellymon]

Thanks, I appreciate it. Will be trying this this weekend.

[Jellymon]

Did a very thoughrough cleaning with four 15min treatments of Montana extreme and some brushing. I completely removed the chemical between treatments. Honestly very little fouling came out and the bore looked the same afterward. The rifling looked pretty pronounced afterward, but it did before the thoughrough cleaning as well.

I followed all the advice I could find. Thorough cleaning, Swabbing between shots, and letting the barrel cool, which resulted in no more keyholing.

So I went to 100yds and shot my 300g bloodlines with 110g of fffg T7. Good news, no keyholes, bad news, the group was a good 6-8” still. Varied my powder charge with no change. Ran out of bloodlines.

Next up was the .44cal 240g xtp’s with 110g of ffg T7. No keyholes but 6” group at 50yds. Dropped the powder charge to 100g and I shot a group at just under 1 1/2”. Finally, progress. I then shot a group at 100 which was around 2 1/2”. Made some adjustments. And ended up shooting a couple groups in the middle of the bull that were around 2”.

Since I’m only hunting deer with this rifle this year I’m going to stick with this load. It has dropped a few mulies and a whitetail for me in the past. Even on shots over 100yds I’ve hit through the shoulders and the .44 240g XTP passed through with no deflection. So I have confidence in them and now that I have the accuracy bit figured out I think I’m good to go.

Thanks for the advice everyone. 

[Sabotloader]

One more thing to try if you get a chance.... This information is directed at 'accuracy' not tumbling.

It sounds like you might also have a 'barrel Harmonic' problem... in that the forearm of your rifle (actually the stock) may have warped some what causing unequal pressure on the barrel in places.

I wrote this several years ago for a guy to check his rifle - so I will just paste it here.  Might be worth a little follow up...  Wish you were closer to Kennewick, I am headed there today - I would really like to check it for you.

Anyway read through and see what you think...

Checking the Fit of Knight stock


Rob, relieving the stickiness of that should be a really easy fix....

I wrote this up for a guy on Hunting Net the other day - i will repost it here. Look through it and see if it makes sense to you. I firmly believe the sticky stock will affect your accuracy...

Quote:
Can i get a little info on making sure i don't have any stock to barrel issues? I have seen info on tv about how a free floating barrel helps and heard of different procedures of seating the barrel. I will be putting a new stock on my gun very soon (broke the original one), and don't want to have issues there.

I can share some information with you for sure... One thing to remember 'floating' a barrel is not the best for accuracy it is the ‘cheapest’ so that is why you see many companies floating barrels. Companies can not afford to spend the time (money) bedding a barrel to the stock properly so the best thing is to 'float' them. With a wood stock the temperature of the barrel on the wood will make the POI change unless they barrel is bedded in glass or some such feature. In a composite stock if the barrel were bedded into the barrel channel correctly the heat would not be a problem but the flexion of the forearm of the inexpensive stock create a POI shift - so the answer 'float' the barrel.

In your case... since I think you said you have a Knight and if you are getting a Knight composite stock you might not have any of these problems. When I put a barreled action in a Knight stock I set the action in the stock and start the lug screw in. Tighten it with the Allen wrench until it starts to pull the action down. Then stand the gun vertically with the recoil pad on the floor. Gently, and honestly i am not that gentle, tap the gun on the floor to assure that the recoil lug is all the way back in the pocket. Then tighten the lug screw up snugly to hold it all in place. Forgot to say make sure the ram rod is not in place.

When you have the lug screw in tight place the gun in a horizontal position and squeeze the nose of the forearm and the barrel together as tight as you can. If there is no movement – you’re done the barrel is seated on and in the barrel channel. Put the ram rod in and repeat the test. If the test is the same you’re done... go shoot it and give it a check for accuracy.

If during the squeeze test (ram rod removed) the barrel moves down into the stock or the stock moves up to the barrel... release the grip and note if the barrel moves (on its own) back to the original location. Everything should be good - the barrel is floating. Next repeat the test again noting where the barrel returns to. At this time grip the barrel and the forearm of the stock and pull them apart easily. If you feel the barrel stick at some point then you have a problem. If the barrel appears to lift slightly but when you release it - it returns to the original location and you feel no points of stickiness - you are good. Put the ram rod in and repeat the test.

During the squeeze testing if you felt some stickiness in the spring of the floating barrel you will then to do some very light sanding in the barrel channel to relieve the tight spot. You might be able to locate the tight spot by running a dollar bill under the barrel and between the stock to locate the tight spot. Do not sand any more than you need, in fact in my little world the thickness of a single dollar bill is the max thickness the barrel should be off the stock. I normal use a strip of white computer paper for this test it is thinner than a dollar bill - heck it might be worth more than the dollar bill also!!!

Hope this might help you... when you get your new stock and if I can help give a shout....

mike

I am headed out to do some trap shooting this morning I will check back in this afternoon to see if you have any questions.... try to find a round dowel approximately the same diameter as the wall on the barrel channel...

[/size]

[Jellymon]

Just tried this. The barrel is fully seated in the stock, no movement when I press stock/barrel together. When I pull the stock/barrel apart there is no stickyness, and the barrel returns to the original position without interference from the stock, and rests in the bottom of the channel.

I did notice that the stock gets pushed down very slightly when I install the ramrod. I’ve been shooting my groups with it removed.

[Jellymon]

So, still an issue. Contacted Knight and they are saying that the flash hole is worn and that installing a new breech plug/nipple should help. It doesn’t seem like a worn flash hole would degrade my accuracy enough to make bullets tumble and 8+” groups at 50yds, but I could be wrong. Any thoughts from anyone here about this?

[jrebel]

My muzzle loader key holed when I tried a certain bullet.  Went back to my original and it shot perfect.   Have you tried different projectiles...manufacturer and weights? 

[Dan-o]

That is just wicked.

I've owned 5-6 muzzleloaders and probably shot at least 1,000 rounds.

Never seen anything like those keyholes....

[Jellymon]

My muzzle loader key holed when I tried a certain bullet.  Went back to my original and it shot perfect.   Have you tried different projectiles...manufacturer and weights?

Yes I've tried quite a few. But the fact remains that these loads and sabots shot amazingly well the first few years I owned the gun.

[Sabotloader]

author=jrebel link=topic=241814.msg3302864#msg3302864 date=1579052166]
My muzzle loader key holed when I tried a certain bullet.  Went back to my original and it shot perfect.   Have you tried different projectiles...manufacturer and weights?

Yes I've tried quite a few. But the fact remains that these loads and sabots shot amazingly well the first few years I owned the gun.

Ok - thinking my thought process over again.  I thought the problem was inaccuracy - I do not think tumbling entered my mind at all.

Tumbling.... normally and usually is caused because the bullet does not reach the rotational speed that it needs for stabilization. Also in that equation is the velocity the bullet is shot at.

I bought my knight disk extreme (western setup with musket caps) about 7 or so years ago. The first few seasons it shot very well with the German musket caps, 100g of FF T7 with 300g bloodlines and 240g xtp. Usually 2”, sometimes 3” groups.

From your writing above - everything I see should insure that stabilization is achieved, but obviously it isn't so....

So the only thing I can not know from here is if you are getting the muzzle velocity needed.  Your load value should indicate you are.

Next then I would start suspecting the sabot used. The sabot must hold the bullet tight enough to insure the bullet does not slip inside the sabot.  To accomplish that the load as you push it down the barrel needs to require enough pressure to force the sabot to compress tightly around the bullet and compress into the grooves of the bore.

Normally but not always key hole is because the sabot slips up the bore without grabbing the lands.  When this happens the bullet never reaches the rotation (revolutions) needed to stabilize the bullet. 

Also if the bullet is slipping in the sabot the same results will happen.

Reading the rest of your post I am inclined to believe the sabots must be slipping across the lands of the bore. So my question to you is 'how much pressure is needed to load the sabot and bullet' down onto the powder?

I am assuming that you are using the factory supplied sabots with the Bloodlines.  They are for a .458 bullet.  The Hornady 240's use a completely different sabot.

You also mention using a Barnes bullet sabot combination... normally these really tight in a Knight and because of that and with the other information you have supplied I really am leaning to the possibility that the rifle bore is the problem.

Knight's thought about flash hole erosion would and can cause a loss of accuracy but really wouldn't associate to tumbling.

I did send you a PM - it should be in your inbox...

mike

[jbeaumont21]

My buddy went through the same thing with his Knight Disc Extreme that he bought about 6-7 years ago.  Finally sent it into Knight and they sent him a new rifle.  They must have made a few bad batches during that time 

I'm thinking you need to send it into Knight for testing to see if its one of the bad ones 

[Jellymon]

The bloodlines I'm using the supplied sabot and I'd say they load with difficulty. The 44cal XTPs I use the green hornady sabots which load stiffly but not too bad and are the best shooting during my troubles.  The Barnes I was using were the 290grain TEZ which loaded very easy and were the worst keyholin/grouping by far. With all three I can't load over 95g without horrible accuracy and keyholing.
So right now I'm just going to try knights recommendations, even though I don't think it's the flash hole, and hopefully they will have me send the rifle in to inspect it.

[Sabotloader]

The bloodlines I'm using the supplied sabot and I'd say they load with difficulty. The 44cal XTPs I use the green hornady sabots which load stiffly but not too bad and are the best shooting during my troubles.  The Barnes I was using were the 290grain TEZ which loaded very easy and were the worst keyholin/grouping by far. With all three I can't load over 95g without horrible accuracy and keyholing.
So right now I'm just going to try knights recommendations, even though I don't think it's the flash hole, and hopefully they will have me send the rifle in to inspect it.

Since it is a Western - you just need to change nipples - that's easy enough.  And I hope that works for you but I still think you will find you have a bore problem.  Wait! another possibility which just now comes to mind - might be the 'crown'. Check the crown very closely for nick or dings...

[kerrdog]

I went through the same thing with a disk extreme.  I tried everything and that rifle cost me a bull one year.  Send it back to knight.  I sent mine back and they sent me a replacement that worked (although I'd already bought an Ultralight and have never really used the Disk Extreme again...heavy.) They said they thought the problem was the way the crown was cut; was destabilizing the bullet as it exited the barrel.

[Sabotloader]

I went through the same thing with a disk extreme.  I tried everything and that rifle cost me a bull one year.  Send it back to knight.  I sent mine back and they sent me a replacement that worked (although I'd already bought an Ultralight and have never really used the Disk Extreme again...heavy.) They said they thought the problem was the way the crown was cut; was destabilizing the bullet as it exited the barrel.

You know that can be a real problem.... I just went through the same thing with one of mine.  I had to re-crown it last week and shot it the next day all the difference in the world.  I am pretty sure my crown problem was my own doing.... to many years shooting that rifle and reloading - pretty sure the reloading with the gun rod and sometimes rubbing the crown with the rod finally created enough wear to give me headaches.

mike

[Jellymon]

So just got my rifle back from Knight. They had it for a few weeks and found that it had loose spots in the rifling so they replaced the whole barrel as well as my missing screw for the secondary safety. Knight made the process very easy, great customer service!

The rifling in this new barrel is much more pronounced than the bad one. Once I get a good chance to shoot it I’ll report back with, hopefully, good news.

[Hilltop123]

So Knight, did you good? Let is know!

[Jellymon]

Well, went to the range today and the new barrel shoots great! After getting close to center and verifying no keyholes at 50yds with 275 bloodlines, I moved to 100 and shot a few groups.

I only had 2 of the Barnes TEZ's left which were the worst shooting ones before, and both of them flew perfect and landed within an inch of each other. The bloodlines did ok with the biggest group at 3 1/2" with open sights at 100. Not one even close to keyholing. Pretty sure I can get better with some load development but overall I now have my accurate rifle back.