New qb 78 has a new transfer port oring



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Offline Grampy ray

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New qb 78 has a new transfer port oring
« on: December 19, 2017, 01:43:45 PM »
I just got a new beaman qb 78 and it looks like it has some kind of black oring on the transfer port.has anyone seen this yet?is it a improvement or is it still restrictive.?
  • MI, USA

Offline lillysdad621

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Re: New qb 78 has a new transfer port oring
« Reply #1 on: December 20, 2017, 05:03:36 PM »
if its not as big as a icemaker tubing ID, you are restricting yourself.
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Offline Grampy ray

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Re: New qb 78 has a new transfer port oring
« Reply #2 on: December 31, 2017, 11:06:12 AM »
Well I had the barrel oring leaking a little so I tore into gun . It has the same old seal that qb have .it was not crushed or off center so it looked like a perfect round o ring.
Since I had it apart I port match the breach to barrel and port matched the probe to barrel. Level the breach transfer port for a better seal and put it back it back together with 1/4 tubeing seal I also took a chopstick into the grub screw hole and put a little pressure on the o rings so it would not get cut like the original o rings . It sound louder so I hope it has a little more power.
« Last Edit: December 31, 2017, 11:23:01 AM by Grampy ray »
  • MI, USA

Offline Neil54

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Re: New qb 78 has a new transfer port oring
« Reply #3 on: January 04, 2018, 03:27:07 PM »
I like a piece of 7mm delrin rod with a 4mm hole for the transfer port.
Have you modified the valve at all.
Neil
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Offline Grampy ray

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Re: New qb 78 has a new transfer port oring
« Reply #4 on: January 04, 2018, 05:08:20 PM »
I used 1/4 inch air brake line for the transfer port it is stiffer than water line tubeing .I did a test fit and it crushed down and conformed to the parts so I use it and seems to be fine. As for the valve all I did is remove the filter that's it.it 50 degrees in my basement so power wise it seems ok for 30 feet shooting it seems to have as much power as my 2100 . I have went  through two refills of gas ,I hope the barrel brakes in better than it is . It's accuracy is ok not steller . Group's 3/8 to  7/16 at 30. I have  2100,880 and a 397 that can rip just one clover leaf at  that range.
« Last Edit: January 04, 2018, 06:19:45 PM by Grampy ray »
  • MI, USA

Offline jackinil

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Re: New qb 78 has a new transfer port oring
« Reply #5 on: January 04, 2018, 08:07:56 PM »
I just did the poly tubing thing for the transfer port on my QB78D. Seems to hoild gas fine. Mine will cloverleaf in my 30 ft basement range if I hold it steady. Using JSB 15.89s. Cant wait for spring to try it in the backyard.
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