QB78 barrel OD?

[superchikn]

I bought my QB78s from Amazon in 2020.
I finally got around to ordering a suppressor and barrel adapter.

My barrel OD is 15mm and the adapter did not fit, too tight.
Apparently the manufacturers QB78 is a little over 14mm.
Can anyone shed any light on this?


Thank You

[rsterne]

Two diameters used, 14mm or 15mm.... I think the base QB78 used the smaller size, and the others used 15mm....

Bob

[Frank]

Have two QB78 with gold triggers. With the digital I have they read between 14.96 to 15.02 mm. these were purchased in the early 2020's..

[superchikn]

Thanks Bob,


Mine is just a basic model i got on Amazon for $69.99.

I can mic mine as can many but not all.
Is there a rhyme or reason  to decode this?

[Ribbonstone]

They do still make both sized barrels.  If there is a logic behind what barrel diameter they use, I’ve not found it...but you would hope they kept it the same within models.

I thought the 14mm versions were restricted to the old original QB78’s, the later 78D’s using the 15mm “like everything else”.

Then they started selling PCP’s.

Then they changed back to 14mm barrels for the Chief PCP (the single shot, 2K fill version).   Have no clue what the  Chief II/Commander PCP’s barrel diameter might be.

CANNOT swear what diameter barrel the 78S you pictured uses. The repeater version used a 15mm barrel…..but it’s possible they used a 14mm.

ANYWAY...as you LDC is a 15mm....it would "rattle fit" on a 14mm.....thinking you just got a bit fatter than normal 15mm barrel.

[CraigH]

QB78D (gold trigger and bolt handle) has 15 mm barrel.

Standard QB78 and QB Chief have 14 mm barrel.

[Back_Roads]

 I have the same gun bought the same year, has a 15mm barrel.

[superchikn]

Thanks for your responses sirs.
I guess Beeman made it clear as mud for us.

[rsterne]

I'm pretty sure the "Deluxe" (D) version with the gold trigger has always used the 15mm barrel.... and I think the QB79 does as well.... and also "AR" versions with the target sights.... The "basic" version is the only one with the 14mm (and the Chief, I guess)....

Bob

[superchikn]

I had assumed mine was the basic model.  Am I mistaken?


https://www.amazon.com/gp/product/B01MU32XXI/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[rsterne]

That is a Beeman, not a QB, AFAIK.... No idea WHAT Beeman does....

Bob

[superchikn]

It is a model QB78S though. QB78s is on the receiver.

[Back_Roads]

It is a model QB78S though. QB78s is on the receiver.

Amazon Add copy says the same. I have that gun 15mm is the dimension, I may bee needing quiet too as plans for a Safe Pack dance in my head.

 Dropped right in an old Crosman 1400 stock.

[Ribbonstone]

For what they are making/selling in co2 rifles....none of the co2's come from the factory with an LDC (neither does the 14mm Chief PCP), it doesn't matter that the muzzle ends up 14.88mm or 15.02mm.  Matters to us, not to them.

AR2078 types do take a sight block....maybe they are made a little more uniform, likely they are hand selected because they came out that way.

The other PCP's do come with muzzle attachments...so I have to assume they pay closer attention to getting a planned part to fit on either by building in enough "slack" to the muzzle attachment or by better control of the muzzle diameter.  Never had a Chief II or Commander, have no idea what the diameter under the LDC might be (could be a short rebated section).

Lot of people buy QB's because they have functional iron sights.  Have to really work at it to get an LDC that allows the front sight to stay on the barrel.

LIKELY your 15mm LDC just had the bad luck to be on the small side and got paired up with a 15.02mm barrel.  Anyone who makes LDC's for QB's has to be aware by now that that kind of miss-match isn't uncommon, and should make suggestions.

[superchikn]

I was reluctant to mention the sellers name as I did not want to cast any aspersions on him or his products.


The issue did not lie with manufacturing or design but simply the fact that QB78s come in two barrel diameters and his design was fitted the his 14.10mm barrel. His is a deluxe model.
  Last night, Friday night, when i discovered the fitment issue I emailed Terry of Buck-Rail and I saw on his site that a reviewer had just reported the same issue two days earlier but the reason was not yet known.


I told Terry of the issues and gave him the measurement of my barrel.  He replied within minutes sending me a photo of a mic on his barrel at 14.10mm.  He said he would pull the product from his site until he had it figured out, at which point I started this thread and brought it to Terry's attention.  By this morning the product description was updated advising of the two different size barrels and to measure ones barrel before ordering.


https://buck-rail.com/product/beeman-qb78-suppressor/


Terry also stated he would refund my purchase and I told him not to but just to drop the updated adapter in my next order when it is ready. 


For anyone who has not ordered from Buck-Rail I encourage you to give them a look.
I have received four orders of 10 or so different products from Terry and I have been very satisfied with each piece- design, manufacturing quality, function and price have all been outstanding.
Perhaps most of all is the great customer service he provides.


I do not know Terry, I just want to pass along my experience with a terrific small business within our hobby.


Thank you all for your input on this barrel size discrepancy.

[Ribbonstone]

While I haven’t used the buck-rail, was aware of it as a good solution for keeping the front sight functional.  He’s aware of the barrel diameter issues, shouldn’t be a problem to get one that fits.

[Back_Roads]

 I had one issue with their slip on being slightly too small for the new C362, I just took and rolled up some sand paper on a pencil and made a precision fit

[superchikn]

I had one issue with their slip on being slightly too small for the new C362, I just took and rolled up some sand paper on a pencil and made a precision fit

Interesting,
Mine fit perfectly.