Out the box .25 BullBoss shot strings Semi Review

[redlined_b16a]

Opened it up and charged to 200 bar.
Buffed the casting from the mags as they would damage pellets.

25.89 grain JSB excat king

200 bar
 1:918.    6:924.   10: 925.     15:922
2:916.   7: 920.    11:925.      16:919
 3:918.   8: 923.    12:926.     17:923
4:915.    9:918.     13:921.     18:917
5:920.                   14:922.      150 bar
 E.S. of 11
3rd mag was.
19:920.    24:897.   
20:909.    25:878
21:910.    26:875.
22:906.    27:855
23:901.    129 bar

So I think it can be improved with the Bob's Mods to valve only.

Shot 30.86 grains average 845fps
And 33.89 grain JSB exact king heavies at and average of 815fps
How does this look to you.
Id like to have 27 shots in the 45 fpe range.
I think its do able.

Trigger is harsh out the box for sure.Gun is very quite so before I chronied it I though it was not shooting over 700fps.
Im impressed.

So I have a couple hundred rounds thru it here's my thoughts.
Compared to my .22 at44 short I really perfer the boss in the woods.On a bipod I think I like the stability the at44 offers.The Boss action wiggles alot in the stock.

Weight Wise they feel the same.Both have varible zoom 3x9x40 scope.
boss has a UTG Leapers with adjustable AO.
AT44 short sports a Pinty China scope.Well worth the $28.
In the woods the Boss wins.The pup design makes the weight so much better than a rifle.The boss feels a couple pounds lighter than it actually is.
I can now make more accurate standing off hand shots more accurately with ease.As a hunter I feel confident with longer distance shots.


27 shots at 40 yards upon break in

The  top middle jsb 25 grain....rest 30 grain cuda and jsb 33 grain....33 grain jsb shot guns at 35 yards

Short airtube on bullboss




Having both calibers and same platforms I will perform more test like .22 vs .25 both 25 grains at 900fps.
According to Hawke Chairgun Pro they should have almost the same trajectory......cept the at44 short didn't shoot the 25 grains well.
I should have had .25 Cal first.
I'd have a .30 Cal now lol......it never ends.

the boss performs so we'll I may not even perform any mods.Its very quiet too.

[drummerboy7816]

Nice.  My .25 BullBoss should be here next week.  I have the same goal as you, 3 mags, around 45 FPE.  Will be following this thread!

[2Beers]

Looks like you received a good one.
When You do "BoB's" mods.. could you post up a few pics.
Or
Direct me to the link of thread. Ive half heartily searched and can't find it. Easy getting lost following all the great information on other threads..ahahahaa.
 
I may go ahead and try it to mine also.

Following along my friend.
More please.

[redlined_b16a]

Bob's Mods
https://www.gatewaytoairguns.org/GTA/index.php?topic=33903.20

[redlined_b16a]

Happy so far.Loves jsb 25 grain.I couldn't crony it as it was snowing but I cranked up the hammer preload by 1 turn and tried to force it to like the heavy ammo......but it still loves 25 grain jsb.Guessing it's near 1000fps.
50 yards are sub 1”groups

[2Beers]

Right on....
Already stretching it legs....ahhaaa.
1000 FPS is cooking I bet with the 25's... would love to see some slow motion targeting  of the pellet threw the Hatsan at that speed.
I haven't dared yet to turn mine up.. Even after 3000 plus pellets in a years time.
Other then some lose screws.. Ive had no problems at all once dealing with the few little quarks right out of the box.
 I'm still very happy with mine.
Just need to get my Hard wood stock started and made... Thinking I'll be golden.
..Keep the info coming...

[redlined_b16a]

Today I turned up the hammer preload to shoot 33 grains at 900fps.Turned 2 full turns Counter clock wise and chronied 932fps on first shot at 2700 psi(stock it shot 815fps).
Second shot 820fps and 3rd 750fps......so as expected hamner screw backs off by itself.

Just about destroyed the transfer port with an ez out to remove it.Vise grips tore it up so it works after I dressed it but I will machine a new one.

The hamner screw has about 12 threads or more but only 7.5 turns are into the hammer so not many useable adjustment turns.

I installed loctite and set at 4 turns.
Too dark to chrony however its tight groups at 35 yards.
Using the first version of the jsb 33 grains.
At 750fps they were all over the place.

I looked into doing the silicone tube mod.......not gonna happen with this new hammer design.it has a spring that will slow the hammer down.Thinking if that spring tension was adjustable it could aid in tuning for efficiency.

Overall enjoying the gun.......not happy about the hamner screw.
And that I have to shim my scope mount to have more left adjustment no matter how I assemble the rail and plastic components.

On the plus I pop soda cans at 100-150 yards.
Head shot several tree rats 45-70 yards so far its overkill for tree rats.
It loves JSB 25 grains but the squirrel and raccoons do not.

[redlined_b16a]

Just to clarify and preload above 4 turns the hammer screw becomes very loose.

[Dan H]

I tried my new bullboss out  that came in Tuesday ... put a 10x40x60 HIRAM scope on it ... at 50 yards when I did my part I was going threw 1 hole over and over or at worse was tearing the center out of a dime size circle ... I can see this bullboss having no problems out to 100 + yards !  ... shoulders a little less weight than my gladius long  that gun I really really ! like ! ...  those LW german steel copy barrels really work well from these 2 ... they are just as accurate as my at44 long with LW barrel or the green mountain barrel .25 on my marauder  ... its just a matter of holding the gun's correctly-consistently  + trigger pull....

my boss showed jsb25.39 fps 931  -  907   first mag  ... so this boss is cook-n-with-butter right out of the box ! 

[redlined_b16a]

Slung alot of lead down the barrel.
Loves JSB 25 grain and benjamin 27 grains.
Everything else not so much.
Cleaned barrel.
Passed about 50 patches thru with hoppes barrel blast till all the black gunk came out.Groups tightened.

Tried to adjust hammer as it lowered fps on its own and found worn threads.
Cleaned and applied plenty loctite not velocity is stable.
I hopped to push 27 grain ammo at 880-900 fps but that is not do able atleast with my gun.
Peak now is 830fps but still with an 11 es for 18 shots.
More hammer preload results on lower fps and massive air consumption.
Seems 25-27 grains is my max weight I can push to the near max.

Not what I expected but its what I purchased.
Long range the gun is not so great.I suspect the barrel needs a nicer crown job like the 11 degree target I put on my at44s-10 .22.
Today there were targets at 70,100 and 120 yards so I can learn my hold overs.
They boss struggles to hit the 100,150 yards.Probly 4" groups.
2 minutes later the at44s-10 .22 right on target.
70 and 100 yards first shots the 150 yards took two shots to find my hold.3rd on target.

The boss never hits the same areas.
At 50 yards the boss does great.Still at44 has the upper hand its modified and re crowned.
Slow air leak somewhere......if I fill to 2700 psi and let it sit forva week without touching it the pressure drops to about 2200.
Will wait to see if I decided if I want a regulator.
With the already acceptable extreme spread I don't see a benifet unless I set fps at 800 with 25 grains and try to get 30 or so shots.Not intrested at thos time.

My dream was 30 shots at 45 fpe which was do able for a Condor.
The boss not so sure with mine anyway.

So am I happy with my purchase.
Not 100% but its an excellent woods walking short range free hand shooter out of the box minus the hammer screw issues.
Its very quiet as well.I can drop two raccoons and the rabbit 30 yards away isn't spooked.
During break in target shooting crows landed in the trees 50 yards to my side and they were not bothered by the sound and Crows are cautious.

Gun needs work for sure.At the discount price I got it for its a great buy.
At full price not so much.
Wish I had continued to buy the Condor SS.It was in my cart until.I checked the Hatsan prices.

[hennigm]

I love my .22 Bullboss.  Very flat trajectory.  Put a huma reg in it set to 130 bar, 873 FPS now compared to 960 without.  Only get 30 good shots out of a max fill.  Its a heavy gun and I wish the trigger was like my HW 110, but it is fairly quiet and easy to move around for shooting pests.  I switched to the 17grn metal mags over the jsb, when cocking I have to have the barrel up so the "sabot" will not rub on the receiver as the magazine rotates.  For the price 440$ from Midway, it is a great gun.  Highly recommend it as a first PCP or addition.

[badgerfarm]

I got my Bull boss on Tuesday this week in .25 cal.  I've been gathering all of the goodies to go along with it.  I had the scope and mounts already but didn't have the foster adapter for the fill probe and it got here today so at least I can fill it.  I have a decent assortment of pellets on hand....mostly JSB but some H&N and some Beeman.  I'm always curious when I'm doing the chrony work so I like to have a pretty big assortment of pellets on hand.  Overall it looks like a pretty high quality setup and from Reading some other posts it looks like it's tuneable.  The thread that I couldn't find is the one where it talks about the screws on the loading lever being too short.  Can someone point me in the right direction?  I wanted to thank Dan H for letting me know about the SMOKIN deal from Field Supply.  $399 shipped to my door.  I hope it performs as well as some of the others that I've read about.  hennigm,  where did you find the Huma regulator for your Bull boss? 

[redlined_b16a]

If I recall the short screws were on some of the earlier models and should no longer be an issue.

Cons with mine so far:
Not very tuneable at all.
Flimsy on a bipod.Plastic flexes alot
Every time I shot I have to re center scope due to flexing plastic.
I had to shim my scopes as the rail isn't center with barrel(tried several scopes)
And the sling posotion is awkward for sure.

Still worth what I paid.

Maybe its tuneable for lite ammo 19-27 grain.
Any heavier.
Not useful for 30-33 grain.I couldn't reached my desired 880-900 fps

[fgwhite]

good looking gun in the pict where both guns are side buy side if the at44 is a long version did you put a short version air tube in the bull boss

[redlined_b16a]

My at44s-10 is the short 180cc airtube.
I put the long tube from the bullboss on it just for comparisons.
I like the long tube on it but with my Hatsan air striper I can not use the long tube 

good looking gun in the pict where both guns are side buy side if the at44 is a long version did you put a short version air tube in the bull boss

[redlined_b16a]

Added an extra rail forward of the trigger gaurd as recommended by 2Beers.
It makes it fell like a better balanced machine and offers more stablity while on a bipod.

I bought some 4 40 gun screws with lock nuts and drilled holes.Be aware of the location you choose because there is a brace inside stopping me from placing it closer to the trigger like I wanted.

Next mods are a barrel crown and Bob's valve  mods and I may experiment with hammer weight.
I really want to push 33 grain a lil faster.
18 shots at 900 fps would make me smile if they are accurate

[badgerfarm]

That's what I would like to see is a 34 gr JSB at 900 plus but I could live with the 25 to 28 gr in that range if they have the accuracy.

[redlined_b16a]

My 25 grain is accurate at 920fps
The 27 grain is accurate at 860fps.

[fgwhite]

gun looks great i liked the looks of the smaller tube how many less shots do you get useing the smaller tube compared to the long version

[redlined_b16a]

I have not tried it with the short tube.Short tube is modified to line up one single transferport to my at44.
It will not line up to the bullboss.

I just put it on to verify it will fit.
I may buy a short tube though as it shaves almost a pound of weight off of the front of the boss.

gun looks great i liked the looks of the smaller tube how many less shots do you get useing the smaller tube compared to the long version