Huben Hammerless K1

Forums PCP Airguns Huben Hammerless K1

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    harrymoreland
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    Khilji, I read a few times that 5.55 works better in the K1.

    Sorry as I realise that's no Help seeing as you have the mold in 5.52,

    I must admit that my mind finds it hard to understand how such microscopic differences can matter.

    please keep us updated, thanks.

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    airgunfans
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    khilji

    huben is not accurate at 15 yards with mp mold slugs 5.52 . The group size is 4 inches  what should I do

    I have tried both 5.52 and 5.55, the latter is much better accuracy wise

    Make sure that you use lube of some kind. I use Krytox GPL 105 oil. I have tried un-lubed slugs right out of the mold and the result was terrible.  I had to JB the barrel to remove the lead deposite inside.  

    As a refinement, I add 3% tin to the lead to make the slugs a bit harder.  The accuracy is better than that achieved with pure-lead slugs. I believe the softness of pure lead results in more deformation when the slug transits from the magazine to the barrel.

    You may also want to check whether the two mold halves are aligned perfectly as I notice that the seam line on the slugs in your photo are very prominent. This is a 5.55 slug coming out from my MP-mold .  The seam line should is quite faint 

    After being pushed through the barrel : 

    This is a 10-shot group at 11 yards. CTC is about 2.5 mm

    • This reply was modified 2 months ago by airgunfans.
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    khilji
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    Thanks for the update today I checked the barrel the slugs are bit free in it choke area is not working I removed the barrel and pushed some slugs out of the barrel with the help of the rod and after I measured it it was 5.56 

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    harrymoreland
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    Huben K1 based question.

    Anyone charging their K1 to 5000psi, and if so How, and with what results, (shot count)

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    cootertwo
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    I wish I had a compressor that would go to 5000, then I'd let you know!😁

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    knifemaker
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    I and several of my friends have been shooting slugs for years. Here are a few things we have learned. Try to size to anywhere between 1 then thou. under groove dia, to no more than 3 ten thou inch over. A full thousandths can make a huge difference. Check .0001 at a time. The NOE System makes this very easy.

     

    Chokes only serve to lead up faster than without for bullets. If you insist on using a choked barrel, size for the choke rather than the barrel.

     

    Best lube we have found is 10 WT silicone RC Shock oil. I get it from the bay or Amazon from Lucas oil.

     

    Fire lapping the barrel, then re crowning makes a huge difference with slugs. My .257 went from needing cleaning for top accuracy at 35-45 shots, to 150+ immediately after the fire lapping and hand polishing, After a few thousand shots, it now will go for 300 + before accuracy drops off. l

     

    I shoot .223, .250, and .257 slug barrels and am currently building a .172. These above suggestions have worked on each and every one of them.

     

    Knife 

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    Kiki
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    I just reassembled my K1 .25 with an unchoked 16MM OD LW barrel and so far its seems to be an improvement, I say this because at 20 yards without even sighting in i am shooting consitent groups with my MP slugs. the reasoning for this change was after looking at and shooting with the original barrel my thoughts were that the original small diameter short choked barrel must have some harmonics problems when shooting the MP slugs, basically I came to this conclusion because when i shoot my K1 .22 with MP slugs it's accurrate and can be pushed beyond 1000fps. the .25 on the other hand lost accuracy even with the slugs above 900fps. i have yet to chrony (by the sound its about 850fps) with the new barrel as i am in a shoot it a bunch of times to get the barrel and mechanism all settled in and then chrony and dial in some settings.

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    harrymoreland
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    interesting stuff Kiki, please update lots, also let us know how the new barrel shoots pellets as well.

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    harrymoreland
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    Hello Knife, Do you believe "fire  lapping" would work on the Huben , considering it Fires from the Mag,as opposed to from the barrel.

    IE the effects of "fire lapping" on the throat of the Barrel ect.

    please don't see my above as me calling into question your findings, I am hoping to learn,

    many thanks.

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    knifemaker
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    The issue with the Huben is the choke. Remove it, or better, put a choke-less TJ's barrel or a L/W in it. I use TJ's mostly, as they have superior metallurgy being designed for firearms. However, he now makes custom ag barrels.

     

    I find it odd that Huben advertized the guns orginally for slug shooting, yet put a pellet barrel in them. So many companies have no idea what it takes to shoot slugs. AirForce has been a huge offender in this regard.they ignored any and all info given to them by experienced slug shooters. And initially failed miserably. Still are!

    The last extreme bench compo long range match was won by AAA airguns all using TJ's, it three different cal's

    I fire lap all  of my barrels. Yes, it will open the lede slightly. But as all slugs should be sized to the barrel, this ins a non issue. Yes, it will open the cylinder slightly as well, which is good as it needs to match the lede in the barrel.

    Knife

     

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    Jammin22
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    So how do you get ahold of TJ and what ;non choke barrel do you go with for a .22cal Huben? Right now I'm shooting 25gr monster JSB with great accuracy. I would like to try some slugs without screwing up my factory barrel.

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    Kiki
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    Harry,

    Other than the regulator setting where it goes above my set pressure its going okay, chrony avg for the MP Mold slugs has been 935FPS Avg, and with the Nielsen 34.7 slugs its right at 950FPS Avg. accuracy at 25 meters is ok for the MP slugs with the occasional flier. much better for the neilsen slugs but since the magazine OD seems like it was designed for a pellet skirt the slug slides around causing jamming and pressure dumps. To alleviate the jamming i have melted beezwax over the neilsen slugs so they arent loose, this isnt my long term solution as i would prefer a magazine similar to my .22 and in the process of trying to source a couple of spare .25 mags to modify them for .250 slugs. another path is i am sourcing a Corbin Press with the size set at .254 and then size the pellets to the magazine with my sizing dies. this path seems risky as i checkd my barrel specs and the lothar barrel is listed at .248 bore dia with a .254 groove dia and the increased size of the slug may cause some issues.

    Since i have plenty of other pellet throwers i am focusing on slugs for the two hubens and maybe the LCS Air Arms .25.

    K  

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    harrymoreland
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    Thank you Kiki, all Huben information is gratefully received.

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