Here is an other spin off thread for the Huben pistol where members can share what ammo they have found works good,....... or bad in their hand cannon.
Huben Huben pistol ammo choice.
- Thread starter Nomadic Pirate 66
- Start date
the varmint knockers .223 28.5gr slugs shoot very well for me in my gk1.
my k1 is one of the 2019 models with the .218 magazine and the .223 barrel and the slugs don't like that at all.
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Steve - This is a picture from one of Gregor’s videos showing the barrel from the K1 .25 with the low number of L&Gs, same as mine. He states that it is ~1:28 twist.
I haven’t measured the twist on mine but 1:28 doesn’t comport with its ability to accurately shoot the 51g Altaros slugs.
I haven’t measured the twist on mine but 1:28 doesn’t comport with its ability to accurately shoot the 51g Altaros slugs.
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About 3 hours of effort, 100 per bag. 40.5 grains, .2225 diameter. Take daily daily as directed
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Well, here's the thing. I'm trying to get a better die made by Corbin. My current one presents a few problems.How about some .254 for your 25cal bros..nice work!
1. For the .25 gk1, full length slugs work fine. However, for the .25 k1, at least the 2021 iteration that I have, if i make them full length, they require a tool to seat fully in the magazine slots. I can make them shorter and lighter to avoid this, but I'd like a die that can make full length slugs if I want that don't need a tool to load. At full length I can make them a bit over 50 grains, but the tool is needed. To not need the tool to seat, they have to be made about 41 grains, barely heavier than the 22s.
2. The extractor pin which forms the nose on that die I have now is a hollow point former. It makes the slugs harder to remove from the pin, they stick a bit, and I have to use both thumbs and forefingers to remove them rather than just one hand's thumb and finger. I can't just tilt them to remove them, it would deform the nose because of how far the hollow point forming pin sticks into the slug. They have to be lifted off. So when I get in a groove, I can make the 22s like 2X faster than i can make the 25s. the 22s dont have a hollow point so much as a small indent. I may see if i can order a different pin that doesn't make a hollowpoint to correct this at some point, but the seating issue would remain. I suppose if I at least solve the hollow point issue on my old die, I can make heavy slugs that seat in the pistol easily but not the rifle, but I'd prefer to make a slug that works in both. I did clock one of the 50.2 grain slugs today at 805 fps, I previously clocked a 46 grain at 860 fps at the same power setting. The 46 is actually making a bit more power by going that 55 fps faster. I haven't yet tested what weight of my slugs is ideal for energy in the pistol. I need to make a bunch at various weights and test all on the same day. Sometimes it seems that even a bit of temp or pressure difference can change my velocities on a given day, so I should test on the same day to make sure it's apples to apples
I made some full length 25 slugs and seated them in the rifle using a tool, them unloaded them so that the rifling marks, which is what makes them require a tool to seat, were visible. If the ogive were just a bit more pointy, I wouldn't have this problem. So I sent these 10 sample slugs to Corbin and told them to replicate them but just make them a bit more pointy to avoid the rifling in the magazine slots. I said I didn't want them to be hollow points, and wanted a flat base. They messed it up in just about every way. They are less pointy, encountering even more resistance from the rifling, they are hollow points, and came with a dish base punch. Corbin is sending a new punch and pin to correct the base and hollow point problem that they messed up, but they haven't responded to my email yet about messing up the slug shape, which will require a new die. I am worried they won't admit they messed up and will want me to pay another $650+ for a new die. I explained very carefully what I wanted, and even sent the example slugs so they could take measurements, so I will be pretty upset if they won't fix it and want me to pay AGAIN. In the past, they have been attentive to my requests, but they are under new ownership now too.
All this is a long winded way of saying that I do intend to make more 25s but I'd like to get the die issues sorted so I can make them as fast as I can the 22s. It's hard to compete with a machine and make it both worth my time and competitive price wise with other slugs. What I do have going for me is a diameter and length that is at least somewhat tailored to hubens specifically.
Here is a pic of the slugs that the botched die makes, they've been seated in the rifle then removed. If you look closely you can see the rifling marks that are causing the issue
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I would prefer to see a heavy slug at a nominal diameter with 2 drive bands to grip the rifling not the body diameter of the slug. The drive bands would also create a tumbling wall turbulence during flight that would create a dynamic boat tail effect limiting the drag vacuum normally associated with flat based slugs performing in a similar fashion to a rear wing on a race car. I think the design would improve the BC appreciably and at the same time reduce bore friction.
You may note that at least on the GK1, the magazine bores are straight at .250" in diameter. This was measured with precision pin gauges .250 Go, .251 No Go. There is however a very short chamfer at the rear of these bores that is designed to catch the tail end of the pellet. My barrel measured at .247 Go and .248 No Go. Ideally the body of the slug should be no larger than .247 and drive bands at .253. As an additional note, rimfire bullets are shaped the same way
You may note that at least on the GK1, the magazine bores are straight at .250" in diameter. This was measured with precision pin gauges .250 Go, .251 No Go. There is however a very short chamfer at the rear of these bores that is designed to catch the tail end of the pellet. My barrel measured at .247 Go and .248 No Go. Ideally the body of the slug should be no larger than .247 and drive bands at .253. As an additional note, rimfire bullets are shaped the same way
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I wonder how different it is from the rifle. I've only ever tried .254s so far in the pistol and they seem to work pretty well. In the rifle though, I tried .250, .253, .254 and a few other diameters that I sanded down .254s a bit to get. 250s were by far the worst, it seemed the ideal diameter is somewhere between .253 and .254. The 254s did better than the 253s. This is of course in my 2021 rifle, for all I know newer or older ones could be slightly different
Unfortunately making driving bands with a Corbin swage press is not possible
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.InterestingYou were there, for the win! The slugged JSB MKII King Heavy pellets mic at 0.2532 and ZAN 0.253 38 grain slugs have just the slightest bit of witness marks from the groove on a small portion the heel.
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If you are just blasting at a gong or spinner at reasonable distances, then the 253's will be fine and less stress on things. If going for longer range accuracy target shooting and hunting, maybe test a box of each and see which has better groups. BTW, the JSB MKII King Heavy pellets have a better short range group from my barrel.
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With those results in mind, and the inevitable variation between barrels, I would suggest trying each size. If you’re anything like me, you’ll always be wondering. Plus, as pointed out by A-h, you won’t be throwing either one in the trash, as you might with a .250.
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Yeah i grabbed a few tins of the exact king heavy mk ll 33.95gr as people across the board have all had good results with them..I’ll probably do 85% of my shooting with those to be honest
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Great news. Corbin did send the new punch and pin for the .2537 die. Even though it's the same shape slug, them being round nose and flat base made all the difference both in seating ability, and in speed of making. I made some at 10.9mm, the longest slug the rifle can hold. They weigh 47.8 grains. They fit in the pistol too.
I think what happened is the round nose makes them long enough that less of the ogive reaches the rifling, so they can seat. Huge sigh or relief here. Will test them in both pistol and rifle next
I think what happened is the round nose makes them long enough that less of the ogive reaches the rifling, so they can seat. Huge sigh or relief here. Will test them in both pistol and rifle next
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I'm currently using JSB 25.4 gr pellets because I want to have the higher velocity at shorter ranges. I am pretty sure the 39 gr JSB IIs will fly better at 100 meters. I use those with my Crown. It has a 1 in 18 twist barrel. The 25.4 gr JSBs are very accurate to at least 50 meters. With these I fill to 300 bar and after 17 shots at 700+ fps, I have slightly more than 200 bar left in the tank.. This setup is very powerful at 25 meters and yet easy on the gun. It's a good compromise.
Additionally, the head diameter is .248" and the skirt diameter is.260. This gives good guidance in the barrel of my GK1 with a min. bore of .247" and at the same time excellent rifling bite at the skirt. As I stated earlier in this thread the diameter of the mag bores is .250 Go and .251 No Go. So correct loading is achieved WITHOUT pressing the pellet beyond fingernail tight. At that point the pellet skirt will reside within the chamfer at the rear of the magazine bore. If the pellet is forced more forward in the mag bore, the pellet may fall into the barrel and jam. Ask me how I know this.
Additionally, the head diameter is .248" and the skirt diameter is.260. This gives good guidance in the barrel of my GK1 with a min. bore of .247" and at the same time excellent rifling bite at the skirt. As I stated earlier in this thread the diameter of the mag bores is .250 Go and .251 No Go. So correct loading is achieved WITHOUT pressing the pellet beyond fingernail tight. At that point the pellet skirt will reside within the chamfer at the rear of the magazine bore. If the pellet is forced more forward in the mag bore, the pellet may fall into the barrel and jam. Ask me how I know this.
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