.177 qb78

[Brutuz]

Bought a .177 QB78 last week. As you might know I like Crosman's very much and this QB78 being a copy of the Crosman 167 it has been appealing for some time and when I had the funds I bought one.

Performs fine out of the box. Having worked on several 13xx'es and 22xx'es I wanted to tweak this one too and got a lot of usefull tips and a sealkit.

I'm leaving the valve alone.

Changed the trigger spring,
replaced the breech seal,
did some de-burring,
enlarged the probe port hole a bit,
fitted a new probe o-ring,
polished the friction faces of the hammer unit,
fitted an additional hammerspring which is .25" compressed,
fitted a do it yourself dove tail rail to accomodate my Airforce bipod
after the last mod, the hammerspring, fitted new barrel o-rings and (again) a new breech seal

It barks a bit more now.

Pitty I don't have a chrony.

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/QB78/QB78DL-Scope-Airforce-bipod-1-800.JPG

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/QB78/QB78DL-Scope-Airforce-bipod-2-800.JPG

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/QB78/extra-hammerspring.jpg

Take I http://www.youtube.com/watch?v=IddDRthnEG0
Take II http://www.youtube.com/watch?v=Wk2woBT2Ix4

Am very happy with this airrifle, the way it looks, how the bolt action works and sounds, the power, the accuracy and.... great value for money.

There's only one minor issue. As soon as the powerlets have been pierced the tube is under pressure. As soon as the power has gone and you want to change the powerlets it's not possible to simply unscrew and let the remainig CO2 escape. You have to dry fire it untill it's empty. Maybe I'll buy the tube kit including de-gassing key shown on Archerairguns.com in the future, hope someone in the UK sells it.

[Brutuz]

Here's Take III

10 meter indoor shooting and shotcount

abt 47 good shots from 2 powerlets

http://www.youtube.com/watch?v=EUFVEg6BB3g

[Brutuz]

Yessssss

I've got a Chrony 8)

Here are the results

click here (http://www.postimage.org/image.php?v=gx14OEQ9)
(RAF / rate of fire)

Do need an indoor light fixture for shooting after dark..

Will take it apart again and pollish again, this time using a powertool.

Will also remove the extra piece of hammerspring to check the difference.

[Brutuz]

Last night's string had a few errors due to bad lighting.

Made my own light fixture using plain 40W bulbs and a piece of aluminium strip.

Did a 16 shot string last night so it was still charged with CO2, had a few errors first emptying last nights powerlets but soon figured the height of some shots was causing that.

Emptied the gun, loaded 2 new powerlets, dry fired twice and had dinner.

After dinner I shot this error-free 50 string using the 7.1 grain H&N Hollowpoints:

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/chrony/chrony20091113QB78.jpg

(No alterations on QB, only had time to make the light fixture)

[HW100/90]

Taking an average of 660fps with 7.1 grain pellets, that is only 6.87 ft/lb:(
Aren't they any more pokey than that?

[Brutuz]

After polishing the hammer unit with a Dremel the average is now 686 fps / 7.42 fpe which is not bad for a .177 co2 rifle that hasn't had a valve mod.

The high on that string was 697 fps / 7.66 fpe.

[Smokeless Coal]

Nice going, can appreciate the work involved in those tests.

[Brutuz]

Nice going, can appreciate the work involved in those tests.

Thank you :)

I enjoy testing and sharing the results :D

Take 4:

Two 10 shot targets to show the grouping and 10 shots on the Chrony using a more common grain pellet:

http://www.youtube.com/user/Brutuz62#p/u/0/YAIlop5qAqQ

[Brutuz]

After tweaking the valvebody:

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/QB78/SHOTSTRING20091121.jpg

boring vid: http://www.youtube.com/watch?v=RBKRRqclQ-M

[Brutuz]

Allthough I was very pleased with the .177 QB78 I sold it and bought a .22 SMK XS78.

Tuned it and bought some brass parts from Gmac (http://www.gmaccustomparts.com/epages/BT3197.sf/en_GB/?ObjectPath=/Shops/BT3197/Categories/XSQB78_Custom_Parts).

What do you think?

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-brass-stock-bolt.jpg
brass stock bolt

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-tube-and-breech-endcap.jpg
brass tube and breech end cap

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-barrelband.jpg
brass barrel band

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-tube-and-breech-endcap-and-bolthandle.jpg
brass bolthandle

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-sighted-silencer-adapter-with-endcap.jpg
brass sighted silencer adapter with end cap

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-left.jpg

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-right.jpg

.22 SMK SX78 standard version with stock and triggergroup from a Deluxe version.

A few vids available on Youtube: http://www.youtube.com/user/Brutuz62

This rifle is powerfull and accurate and easy to tune to -12fpe and if you are allowed (like I am since I live in the Netherlands) it's no problem to tune it even more.

Call me old fashioned but I prefer the standard iron sights to the modern truglo sights.

The downside is the use of CO2. I get only abt 34/35 good shots from 2 powerlets in this state of tune.

[ratgunner]

Allthough I was very pleased with the .177 QB78 I sold it and bought a .22 SMK XS78.

Tuned it and bought some brass parts from Gmac (http://www.gmaccustomparts.com/epages/BT3197.sf/en_GB/?ObjectPath=/Shops/BT3197/Categories/XSQB78_Custom_Parts).

What do you think?

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-brass-stock-bolt.jpg
brass stock bolt

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-tube-and-breech-endcap.jpg
brass tube and breech end cap

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-barrelband.jpg
brass barrel band

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-tube-and-breech-endcap-and-bolthandle.jpg
brass bolthandle

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-sighted-silencer-adapter-with-endcap.jpg
brass sighted silencer adapter with end cap

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-left.jpg

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-right.jpg

.22 SMK SX78 standard version with stock and triggergroup from a Deluxe version.

A few vids available on Youtube: http://www.youtube.com/user/Brutuz62

This rifle is powerfull and accurate and easy to tune to -12fpe and if you are allowed (like I am since I live in the Netherlands) it's no problem to tune it even more.

Call me old fashioned but I prefer the standard iron sights to the modern truglo sights.

The downside is the use of CO2. I get only abt 34/35 good shots from 2 powerlets in this state of tune.

Might be a good idea to find out if our host would deliver to the Netherlands 100 powerlets around thirty pounds,

I use them in my (Wifes) QB78 .22 which in the summer I shoot HFT With over open sights standing for all shots, 38/60 scored, Nice jobs and video.

[Brutuz]

Might be a good idea to find out if our host would deliver to the Netherlands 100 powerlets around thirty pounds,

I use them in my (Wifes) QB78 .22 which in the summer I shoot HFT With over open sights standing for all shots, 38/60 scored, Nice jobs and video.

That's a good price, I have to pay a tenner more for 100. Shippingcosts would be the bottleneck though, and if I'm not mistaken shipping powerlets from the UK to the Netherlands is near impossible.

Thanks for the positive comment on the vids :)

[madcockney1]

Hi Brutuz I,like you have one of these superb rifles.A friend of mine made me a new stock and lots of club members have commented on how good it looks.One question,was the upgrade difficult. I need to know because I have difficulty with my hands due to arthritis and rhumatics. Cheers good buddy.

[Brutuz]

No the upgrade was easy, however I do not know how much your arthritis causes a problem when using tools.

[Stuart_B]

Great project there mate :)

The best I had from my .177 QBD was 10.1 ftibs for about 30 shots (going off memory)

Great fun to work on - I then tried to make it into a carbine so cut the barrel down. Still practising the re-crown as haven't quite got it right :)

Spend more time pulling it to bits and testing, rather than just shooting. Definitely all part of the fun though :D

[Brutuz]

Spend more time pulling it to bits and testing, rather than just shooting. Definitely all part of the fun though :D

Same here Stuart :)

Just fitted an extended hollow probe someone made for me:

http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/XS78.22/xs78-extended-hollow-probe-triballofts.jpg

[razor500]

Just the job for those longer pellets,good pics Brutuz,your site and this one.
Ray...

[Rune_rebel]

Hi.
When I had the QB-79 with a cal 177 barrel and bolt, it shot H&N Baracuda 10,6 grn pellets at an ave 742 fts. That is aprox 13 fpe. Temp ca 20 C.
The gun is heavely modded.
Now it has a cal 22 barrel and bolt, and it shots Daystate Rangemaster 37,5 grn pellets at an ave 558 fts (22 C). That is aprox 25 fpe:D.
My QB-78 DeLux in cal 25 (HW barrel) gives ca 23 fpe at 22 C using 31 grn Baracudas.
All my QBs are gasshogs, and they all use aprox one gram gass (or more) pr shot.
Cheers
Rune

[madcockney1]

Cheers guys for listening to my points of view, one thing i will say ,although unrelated , just recently nearly lost the top of my index finger working on a springer. Everyone should be advised CONCENTRATE and think safety]