Seems like the primary advantage is the .068 pin and tighter firing pin hole to reduce cratering and pierced primers. Does it offer any advantage over a standard Armalite, LMT, whatever bolt for reducing ejector swipes?
JP Hp bolt and swipes
- Thread starter newguy2k3v2
- Start date
No, your not going to have swipes and put a JP HP bolt in and your swipes magically go away. Your swipes can be caused by a combination of things from type of ammo, to buffer weight/setup, gas system, carrier weight and a combination of all the above.
I'm aware of that. I was just curious if the design and tolerances on the jp bolt and ejectorwould show less than an Armalite or other.
I already have a xh buffer and agb. Armalite rifle length gas on a 24" barrel isn't helping me any though.
I already have a xh buffer and agb. Armalite rifle length gas on a 24" barrel isn't helping me any though.
No a non headspaced bolt isn't going to fix your case head swipes. Could be ammo related. Biggest thing that removed all case swipe for me on my 223, 308 and 6.5cm AR's after gas was properly tuned and confirmed ammo wasn't too hot was installing a JP SCS along with testing different spring combos and their Tungsten weights. After finding the right combo by brass went from heavy swipes to looking like it was fired in a bolt gun.
Swipes come from the bolt trying to unlock (rotate) before the projectile has left the barrel and pressure has dropped. When pressure is still high in the barrel, the brass is still expanded against the chamber, effectively sealing it. If the bolt is trying to rotate, but the brass won't rotate with it because it's still under pressure, the ejector will scrape (swipe) the case head. In more extreme cases, you'll get burrs that coincide with the swipe.
This is a product of too much gas, too light of buffer, too soft of buffer spring rate, too hot of ammo, or a combination of several of these.
This is a product of too much gas, too light of buffer, too soft of buffer spring rate, too hot of ammo, or a combination of several of these.
Although the points above are the more correct answer, the JP bolt itself may end up helping without changing anything. The JP bolt has a far superior surface finish on the bolt face than any other bolt I've seen to date. Added to that is their "Enhanced Ejector" which has a slightly domed head from the looks of it and an immaculate surface finish. Although these don't solve the root cause of the issue, they do help it out a bit.
The immaculate and far superior finish on the JP bolt will fix his premature unlocking, gas or hot ammo issues?? Lol. No
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This is the kind of response I was actually curious about. I'm aware of pressure and the other issues that cause swipes. I'm simply curious if you took a rifle with say an Armalite bolt showing swipes and install a jp HP, headsoaced correctly, would they be lessened at all.
Did you read the other responses above? No. A JP bolt will not magically lower the pressure in the barrel. Ask again and we'll tell you the same...
A different bolt won't magically lower chamber pressure???? Wow!!!!
It's not out of the realm of possibility that different geometry in regards to the ejector plunger could affect the shape and severity of swipes, given the same chamber pressure.
It's not the plunger the creates the marks in the first place. It's the hole the plunger rides in...
Yea. What if JP was able to make a design work that the face of the plunger would stop at flush with the face of the bolt and never travel below it. No or absolutely minimal ejector marks. I didn't know if anything was different about it. That's why I asked.
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