KP3 Bolt - Barrel Spacing?

[Toestr]

I have a gen 2 KP and I noticed that the bolt doesn't push the ball into the barrel fully. The rear 2/3 of the ball are in the receiver when the ball is chambered. It seems like this would decrease efficiency since it would allow blowby and the ball would also be accelerating into the tighter bore of the barrel (vs firing out of it and getting the benefit of a seal around the bore). Is the KP3 also like this?

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[Chuck E Ducky]

If you have the oring on the barrel threads it shouldn’t matter.

[capitalpaintball]

Its a design flaw in the Azodin pump line. the ball is not pushed into the barrel, it is fired into it. If you put a barrel thats to tight it tends to break paint. I took a teammates KP3 gun and modded an aftermarket bolt to be longer, so it sets the ball into the barrel and it broke way less paint.

[Toestr]

I thought about seeing if the bolt in one of the other Azodin guns was slightly longer so I could at least get half of the ball into the barrel when chambered. It would probably be better if the bolt had a flat face too.

[Chuck E Ducky]

Man they seem to have a lot of stupid flaws. I thought they were decent shooters but between this and the reg. I would pass on them and just spring for a cocker pump.

[Spider!]

Check for blow back with a ball loaded and one in the open feed neck. I had a super bolt that would shoot 3 feet in the air. It had a ~1/8" gap to the barrel.

The other problem with that style of breech is that the ball can roll away from the bolt face, causing the velocity to vary relative to the distance from the face at the moment of firing.

Once you fix or replace the reg, kp3's work well enough. However, I often see them for prices that put them up there with cocker builds, which isn't what I would start with.

[himurax13]

I have noticed this issue with the KP, KPC, and the KPC+. What I elected to do was to paint the area forward of the bolt with a few layers of clear nail polish in 3 equidistant spots to emulate wedgits and use the stock barrel. Since then, I rarely ever get ball breaks or rollouts.

[Toestr]

So I tried putting a foamie on the stock bolt and it looks promising. It both eliminates the stupid cup in the bolt face and moves the bolt face slightly further forward. The ball now sits about halfway into the barrel when chambered.

There are still a couple problems though.

1. The foamie protrudes slightly into the breach when the pump is fully back which can cause the ball to not fully fall into the breach. This may be alleviated by a force feed loader and/or thinner detents.

2. The ball only sits approximately halfway in the barrel. Not a big deal if you're using freak inserts since they have a uniform bore for the length of the sizer. But if your barrel kit has a taper at the breach end the ball will still have some room to move around. In this case ideally the ball would sit 2/3-3/4 in the barrel.

As shown I just have the AGD foamie sitting on top of the bolt to test the length it adds. Ideally I'd use something like a round ANS foamie or similar.



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[tyronejk]

If adding that small length to the bolt still doesn't get the ball fully in the barrel, is it practical to extend the stroke of the pump? Like drilling the pump handle deeper or something along those lines.

[Toestr]

You're thinking in the wrong direction. You'd want to chop a bit off the body/bolt sled if anything. Extending the pump stroke could help the foamie to clear the breach, but the cocking point for the hammer would still be the same.

[tyronejk]

Ah, right. Going the other way would require significant modification.