Huben .25 Slugs for GK1?

NSA .254 slugs, which actually measure .255, are by far the best slugs for the gk1.

33.6gr slugs are great if you're looking to optimize the cylinder capacity for a full magazine.

Here is a 17 shot mag dump at 15 yards using a bag rest @ ~1 shot/sec using primary arms slx 3x prism.

View attachment 472048
Any chance you could upload this in something other than .HEIC file? Like a simple Jpeg version? I can never get these to open, etc.
 
Any chance you could upload this in something other than .HEIC file? Like a simple Jpeg version? I can never get these to open, etc.
Avs is a better choice the lead composition is softer so they are easier to stuff into the magazine. The nsa have antimony in them which makes the lead harder and the avs are pure lead so they are a little softer. This info was procured from Kelly @ Krazykool who has helped me through the ins and outs of both my k1 and gk1. I’ve used both and he is correct. The 253 fit better but the 254 shot better. Also the zan are pretty good. A little silicone lube also goes a long way.
 
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Why slugs in the GK1?
I’m genuinely curious.
Pellets are super accurate and never cause jams.
I’ve only shot pellets in my GK1 once and they were not as accurate as slugs. My slugs shoot MOA groups out to 110 yards and are sized at .253 diameter which fit the GK1 perfectly. For $50 I can send you a sample pack via priority mail of my slugs: 100 count each in 33gr, 36gr and 40gr for you to see for yourself. Send me an email at [email protected] for more information.
 
New observation. I’ve been shooting aea 34 grain pellets in my gk1 and found that either they are slightly smaller dia. Or skirts thinner but when you seat them they travel too far into the mag and are causing jams and air dumps. I was hoping to standardize my pellets and move over to all Aea but alas I guess that’s not going to happen. Upshot is that I learned how to disassemble and reassemble my gk1. Not something I like to do unless it’s necessary but found it to be easy. Word of caution is make sure the gun is completely degassed or removal of the air tank will turn into a large projectile (air cylinder) will go sailing across your workspace and definitely startle you.
 
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NSA .254 slugs, which actually measure .255, are by far the best slugs for the gk1.

33.6gr slugs are great if you're looking to optimize the cylinder capacity for a full magazine.

Here is a 17 shot mag dump at 15 yards using a bag rest @ ~1 shot/sec using primary arms slx 3x prism.

View attachment 472048
Sorry to resurrect this, but I bought a bunch of NSA .254 38.5grn slugs, and I cannot get them to seat in the magazine. Are you just forcing them in?
 
Sorry to resurrect this, but I bought a bunch of NSA .254 38.5grn slugs, and I cannot get them to seat in the magazine. Are you just forcing them in?
absolutely. I have to really push my 42 g AVS slugs in there. It should be such a tight fit that you need to grab the other side of the mag to assist.
 
Man. And they don't jam?? Just using my fingers I was hesitant to force it in because clearing jams on this gun is just such a fun time.
The opposite. This is what prevents jams and gives you a good seal for the air. The tighter fit prevents the slug from moving. If you take a slug and seat it in the barrel you should have to use force to push it through the rifling. The mag on the GK1 is actually rifled. Years ago I thought the pellet/slug should be able to move through the barrel with as less friction as possible. Makes sense, right. Well you'll be losing fps because the air will be going around the slug. My avs slugs actually have fingernail marks on the base from pushing them in. 42 grain AVS and you'll never have a jam again. Im sure there are other pellets/slugs just as good. One more tip - you dont want to be shooting a heavy slug (38 grains and above) on low power setting.
 
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Sorry to resurrect this, but I bought a bunch of NSA .254 38.5grn slugs, and I cannot get them to seat in the magazine. Are
The opposite. This is what prevents jams and gives you a good seal for the air. The tighter fit prevents the slug from moving. If you take a slug and seat it in the barrel you should have to use force to push it through the rifling. The mag on the GK1 is actually rifled. Years ago I thought the pellet/slug should be able to move through the barrel with as less friction as possible. Makes sense, right. Well you'll be losing fps because the air will be going around the slug. My avs slugs actually have fingernail marks on the base from pushing them in. 42 grain AVS and you'll never have a jam again. Im sure there are other pellets/slugs just as good. One more tip - you dont want to be shooting a heavy slug (38 grains and above) on low power setting.
Agree with all of this. I have found the sweet spot to be NSA 33.6grain to get through a full mag at around 50 FPE very consistently and they shoot better than AVS and everything else ive tried. I hear Altaros ATP smooth (the bigger diameter) work very well but they are too heavy to get through a full mag without too much power/fps spread.
 
Avs is a better choice the lead composition is softer so they are easier to stuff into the magazine. The nsa have antimony in them which makes the lead harder and the avs are pure lead so they are a little softer. This info was procured from Kelly @ Krazykool who has helped me through the ins and outs of both my k1 and gk1. I’ve used both and he is correct. The 253 fit better but the 254 shot better. Also the zan are pretty good. A little silicone lube also goes a long way.
I tried various Zans, various AVS calibers and grains, and other variants. NSAs performed significantly better in my setup, but every setup is different.
 
The opposite. This is what prevents jams and gives you a good seal for the air. The tighter fit prevents the slug from moving. If you take a slug and seat it in the barrel you should have to use force to push it through the rifling. The mag on the GK1 is actually rifled. Years ago I thought the pellet/slug should be able to move through the barrel with as less friction as possible. Makes sense, right. Well you'll be losing fps because the air will be going around the slug. My avs slugs actually have fingernail marks on the base from pushing them in. 42 grain AVS and you'll never have a jam again. Im sure there are other pellets/slugs just as good. One more tip - you dont want to be shooting a heavy slug (38 grains and above) on low power setting.

Well you aren't wrong. I had to tap them in with a dowel but they didn't jam. I just can't get over how damn tight they are. And I have like 1200 of them so I have to live with it!
 
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Well you aren't wrong. I had to tap them in with a dowel but they didn't jam. I just can't get over how damn tight they are. And I have like 1200 of them so I have to live with it!
Yep, when I bought my GK1, previous owner said the AVS .254 42gr works great. I bought 400 slugs and I only shot maybe 50 because they're difficult to load. I guess you can say I'm not too experienced in putting things in tight spaces... lol. I went back to pellets. I've noticed the JTS dead center are a bit wider than most other brand pellets and has a tighter fit in the GK1 thus having a smaller group at 15 yards. I was shooting JTS .25 25.39gr. I ordered some JTS .25 33.80gr and some in 29gr. We'll see how they shoot. I use my GK1 to go small game hunting. It works great so far and at maximum, I am shooting 50 yards. I did add a pistol brace to my GK1.

Huben GK1 Side.jpg
 
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I don't shoot slugs for both cost and application reasons. Yes, Weevil is correct the Gun will shoot to a 1 o2 MOA accuracy at 100 yds., but you are very unlikely to shoot any pistol to that level of accuracy. I have hit crows and pigeons at 100 meters, but it's pretty much luck with a pistol. If you use a reflex sight, the dot is likely to exceed 6 inches at that distance. My GK1 is zeroed at 25 meters and I need about a 24 to 36 inch holdover at 100 meters. The biggest reason not to shoot slugs is the magazine's design. It is designed for Diabolo pellets. The magazine bore on my GK1 is exactly .250". Retension occurs because at the rear of each magazine bore there is slight chamfer and the skirt of the JSB pellets are .260" in diameter. It is the tail end of the pellet skirt that locks into that chamfer preventing the pellet from shifting forward and potentially jamming in the barrel. Most slugs are made via extruded lead wire. That process does not allow a shape that will lock into that chamfer. Slugs could be cast with a drive ring to lock into the chamfer, but none currently are commercially available.to my knowledge. If slugs were the option of choice, a redesigned magazine bore utilizing a slight forcing cone would solve the jamming issue similar to the Webley .455 pistol.