New Knight Ultra-Light New Owner Observations + Stock Sights Shooting Low

mcorbeille

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Aug 20, 2018
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Minneapolis, MN
I recently picked up a Knight UL .50 cal 209 bare primer for MZ elk in Colorado. I'm using 300g Thor Hammer bullets, BH209, and Federal 209A primers.

I've only had it out to the range twice. The first time was quite the learning experience. I was getting a ton of primer blowback making every primer get stuck in the bolt. I didn't know about the refiring trick to seat the primer cup at that time so I was prying out every primer with a screwdriver. I only shot 6 rounds that trip and left frustrated.

I went home and began researching. I found all the threads on primer blow back and that this is a fairly common issue. Rather than shim the factory breach plug, I opted to send my barrel out to Jeff Fisk at Bestill Creations for his custom breach plug.

I took it out to the range yesterday with Jeff's new breach plug it shot like a dream. Absolutely zero primer blow back. Not only did all the primers just fall out of the breach plug shiny clean, when I got home there was no carbon fowling to clean out of the action. Perfect, problem 1 solved.

Now on to the next issue I noticed. This one is with bullet selection. I used the Thor sizing pack and landed on .501 because I could barely get the .502s through the bore. Well, after my first range trip with the .501s, they are now easily sliding down the bore even with fouling build up. I'm guessing firing the first few rounds knocked down a bit of burr on the rifling? In any case, I found @FrontierGander's post on resizing Thor Bullets and I'm ordering up a caliper to resize my .501 bullets to .502. I don't have the caliper yet but I think this will be simple enough solution. Problem 2 solved.

On to my last and final issue, the stock fiber optic sights. If I adjust the rear sight to the very top position on the ramp I am right on @ 50yds with 110g BV BH209 & 300g Thors. At 100yds I am shooting about 6" low. I'm out of ramp travel on my rear sight though, so I either need a lower front sight or higher ramp on the rear. I haven't talked to Knight yet since it's the weekend, but does anyone have an suggestions? I'm considering replacing the sights entirely with a ghost ring setup if anyone has any suggestions that include fiber optics and a ghost ring rear with enough adjustment for 100yd zeroing.

Thanks in advance for any help guys!
 
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mcorbeille

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Has anyone tried the TruGlo sights on their Knight? I'm not sure they will fit a Knight but they look like a decent hunting sight, a bit more precision than the stock sights, and more rear sight height adjustment with a taller ramp.

 

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See if you can cut a thin plastic pop can shim and place it under the rear sight and screw it back down. Local hardware store may have a slightly longer screw just in case you need to put another shim under it. 6" at 100 yards won't take much of a shim.
 
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mcorbeille

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Good idea, I hadn’t thought of just shimming the rear sight. I’ll see what I have lying around and give that a try. Thanks [mention]FrontierGander [/mention]


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mcorbeille

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So I talked to Knight about my UL shooting 6" low at 100yds with Thor bullets and they said they heard from customers over the years that Thors don't seal well. Their theory is the rear cup isn't sealing well and allowing gas to escape, thus lowering pressure and resulting in me shooting low at 100yds. They recommended I try to Federal B.O.R. Lock bullets instead. What do you guys think? Is the Thor rear cup thin/soft enough to expand and seal well?
 

txhunter581

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I think the guy you were talking to may have started happy hour a little early. No, I don't think the bullet is the problem. He just doesn't want it to the his guns problem. And it isn't. It is the sight on this particular gun. It is very common with these guns to have to change the sight to get where you need to be.

I have sometimes had bullets hit lower when I RAISE the amount of powder. Has as much to do with the barrels harmonics as it does with the force used.

If what he was saying was true, you would not have gotten a decent group (don't know that you did). Gas leaks like he is talking about would probably ruin accuracy. Not a bad idea to try the Federal BORs as that is a good bullet, but I would bet you still have to change something with the sight to raise the point of impact and you would have wasted more time and money. So if you were getting decent groups with the Thors, I would stick with them and change your sight.
 

mvmnts

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Feb 2, 2017
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Longmont, CO
So I talked to Knight about my UL shooting 6" low at 100yds with Thor bullets and they said they heard from customers over the years that Thors don't seal well. Their theory is the rear cup isn't sealing well and allowing gas to escape, thus lowering pressure and resulting in me shooting low at 100yds. They recommended I try to Federal B.O.R. Lock bullets instead. What do you guys think? Is the Thor rear cup thin/soft enough to expand and seal well?
Hate to resurrect this thread, but I'm curious if you ever tried the federal bullets. Reading this whole thread, it's like you're me. I ran into all of the same issues with my Ultra-lite back in 2019. I'm looking at trying the federal bullets this year for a late season hunt, I am thinking I'm done with the THORs, they are impossible to seat consistently. They either shift and are too loose or are really tough to seat. Still have to fix my blow back issues. I'm waiting to hear back from Knight before I try to shim or get something custom made.
 

Str8shtr

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Oct 4, 2017
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Try more or less powder and see if that changes point of impact. Where the bullet starts in the barrel can have a big affect on the vertical.
 
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mcorbeille

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I tried the 270g copper B.O.R. Locks @mvmnts and they shot pretty much identically to my 300g Thors with iron sights; though they were easier to load. At ~110yds I shoot 6" low with the stock iron/fiber optic sights adjusted as far as they will go. If I aim at the top of the 12" target I'll hit center. For my elk hunt earlier this year that was my plan, just to hold a little high if I was reaching out that far. It definitely seems like a sight issue to me. I haven't decided what I'm going to do about it yet.

As far as blow back is concerned, hands down I would send your barrel to Jeff at Bestill Creations for his custom breach plug. I don't have any experience with the shim solution but I've put at least 30 rounds through it with Jeff's breach plug and every primer has just fallen out of the bolt with nothing more then a slight bump of my hand. It's easier to clean and way more enjoyable to shoot. Prior to the Jeff's breach plug the action would get extremely fouled and I had to pry the primers out after almost every shot. It was pretty disappointing for a brand new gun honestly, but the Bestill plug changed that entirely.

If you find a solution to the sights, LMK.
 
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mvmnts

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Longmont, CO
I tried the 270g copper B.O.R. Locks @mvmnts and they shot pretty much identically to my 300g Thors with iron sights; though they were easier to load. At ~110yds I shoot 6" low with the stock iron/fiber optic sights adjusted as far as they will go. If I aim at the top of the 12" target I'll hit center. For my elk hunt earlier this year that was my plan, just to hold a little high if I was reaching out that far. It definitely seems like a sight issue to me. I haven't decided what I'm going to do about it yet.

As far as blow back is concerned, hands down I would send your barrel to Jeff at Bestill Creations for his custom breach plug. I don't have any experiment with the shim solution but I've put at least 30 rounds through it with Jeff's breach plug and every primer has just fallen out of the bolt with nothing more then a slight bump of my hand. It's easier to clean and way more enjoyable to shoot. Prior to the Jeff's breach plug the action would get extremely fouled and I had to pry the primers out after almost every shot. It was pretty disappointing for a brand new gun honestly, but the Bestill plug changed that entirely.

If you find a solution to the sights, LMK.
I didn't have any problem with the stock sights actually. I hunted them last year no problems, but have since switched them out to a peep anyway. That's probably your best bet. I will definitely talk to Jeff, hopefully he can get me setup before December. Thanks!
 
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