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PostPosted: Mon Dec 25, 2017 1:45 pm 
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Location: Coalmont BC
There were a couple of perfect sized boxes under the tree this morning, and I was hopeful they contained what I wanted.... Here is what my darling wife gave me....

Image

It's a .22 cal Beeman Chief PCP, and the scope is a BSA 4-14 x 44 FFP Side Focus with 30mm tube and extended MilDot reticle.... The scope looks a bit big mounted on that gun, but it will be going on my new 6mm PCP project gun anyways.... It is my first FFP scope, and it will be interesting how I get along with that concept.... I stole a scope from my Hatsan AT-44 Long before I gave it to my son for Christmas (and replaced it with a Leapers 4-16 x 50 AO).... The scope from the Hatsan will be going on the new .257 PCP project I am working on concurrently with the 6mm.... It is an older Hawke 6-18 x 44 AO with an SR12 Reticle.... Both scopes should be good for up to 150 yards or beyond, which will be appropriate for the new guns....

The plan for the Chief is to shoot it as is to get a baseline with a bunch of pellets.... and then tear it apart and see what magic I can work on it.... I don't even know when that will happen, maybe not until next winter.... it will depend on how long my current projects take to complete.... Oh, and I finally found some of the new .22 cal Redesigned JSB 25.4 gr. Exact Monster pellets, they will arrive after Christmas.... I'm hopeful I can tune up the Chief to make good use of them, if they prove to be accurate in it.... If not, then I'm sure the 18.1 gr. Heavies will do a stellar job.... Incidently, the Chief weighs 6.75 lbs. naked, and 8.5 lbs. with that big scope on it.... 8)

Ahhhhhhh it should be a very good year.... :o

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Mon Dec 25, 2017 5:18 pm 
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Location: Meaford, Ont.
Very Nice. Does she have a sister? LOL J/K


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PostPosted: Mon Dec 25, 2017 5:37 pm 
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Dang. All I'm getting is a treadmill. The wife is trying to tell me something? Congrats on the great gift.

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PostPosted: Mon Dec 25, 2017 7:17 pm 
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Location: Coalmont BC
I cleaned the barrel, removed the open sights and stuck a cheap scope on it.... filled it to 2000 psi and it seems to hold air OK.... so I ran the six different weights of JSB Exact pellets through it.... I did each Chrony string from 2000 psi, and stopped when the first shot dropped below 90% of the highest velocity, and here are the results.... For the number of shots within a 10% ES, drop off the last shot in each string.... so that is only 15-19 shots.... This is fewer shots than the original Disco, from the same pressure fill and at similar FPE.... despite having a slightly larger reservoir.... one of the drawbacks of a shorter barrel (21" vs. 24")....

Image

Note that in every case the first shot was the fastest.... and only the first half of each string fell within my usual 4% ES.... Only with the 33.6 gr. Beasts was there a plateau before the decline.... This means that other than for that pellet (which IMO is way too heavy for a stock Chief), only the first 7-10 shots are within a 4% ES.... This is an indication that, at least in my gun, the hammer strike is a bit too much for the 2000 psi rated fill pressure.... In fact when the gun is filled to 2000 psi on the gauge, the gauge on my Great White says 2100 psi, so it's not a matter of the gauge on the gun reading low, either.... While I was testing, I also shot strings with my BBT 27.4 gr. HP and BBT 29.6 gr. FN bullets.... They are "as cast", and measure 0.217" at the head and 0.219" at the driving band.... I have no idea what the barrel on the Chief measures, but their velocity and energy fit right in with their weights compared to the 25.4 gr. JSB Monsters and 33.6 gr. JSB Beasts.... so I can only assume they are about the right size.... The strings would have fallen right in between those two lines on the chart above.... and they both had a plateau of about 7 or 8 shots before the velocity started to drop....

I shot each string into a target 20 ft. away, at the other end of my shop, to get some idea of how the gun grouped.... as expected, all targets were one ragged hole (they better be at that range with 16-20 shots).... The worst group was the 13.4 gr. RS, the 14.4 gr. Express were much better, the 15.9 gr. Exact the best, closely followed by the 18.1 gr. Heavies.... The 25.4 gr. Monsters (the original design, I don't have any of the "redesigned" ones yet) were noticeably larger, and the 33.6 gr. Beasts were larger again, but still tighter than the 13.4 gr. RS.... The BBT HPs grouped the same as the 33.6 gr. Beasts, and the BBT FN were slightly worse, but still marginally better than the 13.4 gr. RS pellets.... The tightest group (15.9 gr. Exacts) was about 1/8" CTC for 18 shots, and the worst (13.4 gr. RS) was about 1/2" for 16 shots.... The 14.4 gr. Express and the 18.1 gr. heavies both did about 3/16" C-T-C for 17 shots, and clearly the middle weight pellets (14.4 - 18.1 gr.) shot the best from this barrel at this limited range.... From past experience, I would expect them also to shoot the best outside at longer ranges as well....

Here is a summary of the energy and efficiency with each pellet....

13.4 gr. JSB RS - average 854 fps / 21.7 FPE @ 0.86 FPE/CI
14.4 gr. JSB Express - average 845 fps / 22.8 FPE @ 0.89 FPE'CI
15.9 gr. JSB Exact - average 817 fps / 23.6 FPE @ 0.91 FPE/CI
18.1 gr. JSB Heavy - average 791 fps / 25.1 FPE @ 0.98 FPE/CI
25.4 gr. JSB Monster - average 712 fps / 28.6 FPE @ 1.11 FPE/CI
27.4 gr. BBT HP - average 689 fps / 28.9 FPE @ 1.12 FPE/CI
29.6 gr. BBT FN - average 671 fps / 29.6 FPE @ 1.13 FPE/CI
33.6 gr. JSB Beast - average 642 fps / 30.7 FPE @ 1.16 FPE/CI

The Chief has a 21" barrel, and I estimated the reservoir at 9 CI (~148 cc) to calculate the above efficiency numbers.... The ending pressure was over 1300 psi for the lightest pellets (shortest string), and over 1100 psi for the heaviest pellets (longest string).... and the gun used between 41-43 psi per shot.... All pressure readings were from the Beeman gauge, which has 200 psi increments, so estimating the pressure within less than 50 psi is in reality "guessing".... However, as you can see, the heavier the pellet the greater the total energy in the string, and the higher the efficiency, which is pretty typical for a PCP, particularly one that is "oversprung" and wasting a lot of air with the lighter pellets.... In reality, Beeman have opted for higher velocity numbers over a proper bell-curve, much like Crosman did when they "retuned" the Disco by adding a heavier hammer spring.... This is a wasteful way to tune a PCP, I wish Beeman had done better.... It is begging to be detuned a bit to trade off a bit of power for more shots.... but of course there are other alternatives.... Unless Beeman are hiding one inside, there is no external preload adjuster to easily accomplish a retune....

Now that I have about 150 shots through the gun, I can comment on the trigger, and action.... The bolt operates reasonably smoothly, and I prefer the "cock on open" to the original QB cocking, I don't like not being able to feel the pellet seat in the barrel when I close the bolt.... The trigger is a typical QB trigger, and although Beeman say it is a 2-stage, the trigger pull is heavy enough I really can't tell.... There seems to be a slight increase in trigger pull just before the sear releases, but the initial travel is long and hard, and there is a bit of creep in the "second stage" (if it even exists, I'm still not convinced).... Some work on the trigger will be the first thing I do.... and pulling the receiver off to see what the porting is like will happen pretty quickly as well....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Mon Dec 25, 2017 7:27 pm 
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Location: Winnipeg, Canada
What diameter is the bbl? Is it a plain 78, or the heavier 14 mm "a" series?

Ran into the nose dive curves with the un-modified qb valve on my home build. My solution was backing off on the hammer spring, and slightly lightning the poppet return....
Not quite the speed you're getting, but still a respectable fairly flat mid 7's with the jsb heavies. My strings were actually 19 shots, but for the sake of consistent velocities I refill at 17 shots....

-D.S.

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PostPosted: Mon Dec 25, 2017 9:34 pm 
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Location: Interior BC
That's a beautiful rifle!! Just love that BSA 4-14 x 44 scope too.
Thx for all the test results are you going to stick with the JSB 25.4 gr. ?


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PostPosted: Mon Dec 25, 2017 10:43 pm 
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Location: Coalmont BC
Barrel is 14mm diameter, same as the standard QB, not the 15mm diam. version found on the deluxe.... :cry:

The main tube is larger than a QB, at 26mm OD instead of 22mm.... don't know about the wall thickness yet, whether 1.5 mm or 2 mm (likely the latter).... Either way, it will be a lot bigger than the 19mm ID of a QB tube....

I am hopeful that after modding I can shoot the new, redesigned 25.4 gr. JSB Monsters, they are supposed to be a lot more accurate in many more barrels.... I only had one gun that liked the old ones, with the cylindrical middle, and that was my B-51 (now sold).... It shot them lights-out at 50 FPE.... AGS carries the new Redesigned ones....

https://www.airgunsource.ca/en/jsb-matc ... al-25.html

I just ordered some.... If I can make this puppy breathe well enough to hit 50+ FPE, they should be just the ticket.... or alternately my 27.4 gr. BBT HP bullets.... or the 29.6 gr. FN solids....

Image

These are the wound channels from the very similar .25 cal BBTs.... about 900 fps in melt-and-pour soap.... HP above, FN below....

Image

The HPs are vicious the way they open up.... These were recovered from the soap block above.... FN at top, HP at bottom....

Image

I haven't got enough experience with them yet to know the ideal size for optimum accuracy, and that will be different with this barrel anyways, most likely.... but they sure make a mess of a GS or Marmot....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Mon Dec 25, 2017 11:05 pm 
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congrats on the new toy Bob... 8)

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PostPosted: Tue Dec 26, 2017 12:08 pm 
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Location: Montreal are
I have exactly the same rifle but I haven't try it yet because I don't have a hand pump.


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PostPosted: Tue Dec 26, 2017 1:52 pm 
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Location: Coalmont BC
Please note I have changed the name of this thread.... Eventually the "Merry Christmas" part will disappear also.... to make the thread easier to search....

Today I pulled the gun out of the stock and removed the trigger and rear plug to have a look.... You have to put the safety on the "safe" position and drive it gently out of the trigger before you can slide the action out of the stock, typical QB trigger.... Here is a photo of the stock trigger with the side plate removed....

Image

Note the generous sear engagement, which causes the long travel.... Also note the stiff trigger spring, which is sitting crooked.... When you squeeze the trigger, just about where the sear releases that spring binds on the edge of the hole, causing that weird "second stage" feel I had noticed.... This is NOT a 2-stage trigger, despite what Beeman say in their manual.... ::) .... However, it soon will be.... ;)

When I removed the rear plug and took out the spring I found three things.... you can see them in the photo below....

Image

First, the back end of the spring was just cut off, the last coil was not closed.... Secondly, there was a single washer behind the spring.... Thirdly, and most interestingly, there was a threaded insert with a hex hole in the back that you can adjust with a 5mm allen key from the back of the gun.... This provides an EXTERNAL PRELOAD ADJUSTMENT.... Mine was 4 turns from full in.... That washer is important, don't take it out.... The spring and washer are 10mm OD, and the threaded insert is 10 mm x 1mm threads.... The rear of the housing is drilled and tapped for that thread, which means that the ID is about 9 mm.... This means you can't remove the spring through the back hole.... However, the front of the housing is drilled over 10mm, to allow the washer and spring to slide freely.... This creates a shoulder inside the housing where the threads stop.... The washer prevents the spring from going any further back than that shoulder, no matter how far you back out the threaded insert.... Without the washer, that point on the spring might get caught in the front of the threads, or damage them.... This arrangement is quite cleverly designed to give a range of preload adjustment equal to the length of that threaded insert, which is 10 mm.... Because the threads are slightly tapered on the ends, mine actually had about 9.3 turns of travel, which works out to 0.366" of adjustment.... If you back the screw out too far, the washer limits the minimum preload.... If you try and get too much preload, the threaded insert runs out of threads and just spins in the hole.... You can bet when I reassemble the gun, I will be finding out the range of adjustment you can get with this well designed arrangement....

but first I need to fix up this trigger.... ::)

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Tue Dec 26, 2017 2:41 pm 
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Location: Coalmont BC
I removed the trigger, spring and sear, here is what they look like stock.... I rubbed the sliding surfaces lightly with 400 grit to highlight the imperfections for the camera....

Image

The trigger is cast, and actually pretty smooth, although there is a bit of fine pitting on the surface that slides along the sear.... The sear, on the other hand, is a mess.... All three rubbing surfaces have heavy lines cutting across the contact areas.... The surface in the photo above slides across the top of the trigger after the sear releases, so not important for trigger feel, but it is for smooth hammer release.... The tiny spring plunger in the photo above will be used to create the second stage....

Image

In the second photo, you can see the stock (heavy) spring, and a typical spring I might replace it with.... longer and lighter.... This photo of the sear shows that it is a real mess.... The upper surface is what locks the hammer in place.... those lines won't affect trigger feel, but they will affect smooth and consistent hammer release, and could even cause wear on the hammer.... You can actually see a burr on the top edge, right where it grips the hammer.... The lower surface is the one that is critical for smooth trigger pull.... Just look at all the lines running across it.... and imagine what that will feel like as you squeeze the trigger....

Time for some TLC with 220, 400, 600 and 800 grit wet-or-dry sandpaper.... It is critical not to change the SHAPE of the contact surfaces, just remove the roughness and polish them.... Stay tuned....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Tue Dec 26, 2017 3:58 pm 
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Location: Montreal are
Seal kit exist for this rifle?


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PostPosted: Tue Dec 26, 2017 4:07 pm 
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Location: Coalmont BC
Dunno.... all the seals will be standard O-ring except the poppet....

Anyways, a half hour of work makes a WORLD of diference.... Here are the trigger to sear surfaces.... The short surfaces are the "active" ones that affect the feel and smoothness of the trigger pull.... the longer, curved ones slide over each other after the trigger breaks....

Image

and here are the surfaces that contact the hammer.... The short one holds it back and the long one contacts during cocking....

Image

I expect a huge difference, time to put it together, and install the lighter spring and 2nd stage plunger.... back soon....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Tue Dec 26, 2017 4:47 pm 
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Location: Vancouver Island BC
LoL I have been look at that gun i sold all my pcp gun and almost all my other but now your not helping Bob ..


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PostPosted: Tue Dec 26, 2017 5:54 pm 
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Brent, you know you waannntttt one !!!

In order to install the 2nd stage spring plunger I removed the overtravel (middle) adjustment screw, ran a #36 drill through the hole, and re-tapped it 6-32 for the plunger....

Here is the trigger re-assembled.... the first photo shows the trigger at rest, note that I have adjusted the upper screw so that about half of the sear is engaged.... The sear would be rotated clockwise until in contact with the trigger when it is holding back the hammer.... The more the sear is engaged (the further you back out the upper screw) the longer the first stage travel is.... Note the gap between the trigger and the tip of the 2nd stage plunger....

Image

The second photo shows the trigger pulled until it has just contacted the 2nd stage spring plunger.... Only about a third of the previous sear engagement is present.... any slight additional movement of the trigger will fire the gun.... The position of the 2nd stage plunger controls how much sear is engaged when you feel the increase in resistance.... The adjustment is very sensitive, make sure you have enough engagement that the trigger remains safe at this point....

Image

I have replaced the spring with a much lighter one, and the pull weight changes noticeably when the trigger touches the plunger.... I will make final adjustments after installation....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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