Finally, some chronograph numbers on my carbine

[JMJinNC]

Now that the Canadian Postal strike is over, I finally got my Combro CB-625 from Nikkonos in Montreal, PQ. Set up my carbine (Boss Hogg) in front of the pellet trap on my shooting rest, and started popping away.

I compared the Combro to a Shooting Chrony Beta Master that I borrowed. Very good correlation. Also compared the carbine pellet velocity to a stock PC77 (refurb) pistol that I borrowed. In summation, the carbine loves Crosman Destroyer EX pellets. This carbine will also stack Remington pointed pellets, so the large spread seen with those pellets is misleading.

Also, the upgrade in velocity from stock is almost 200FPS at 10 pumps. Chalk that up to the 24" barrel, FT piston/valve, and Brutuz seal.

My impressions on the Combro CB-625 Mk4... AWESOME! Compact, accurate, light weight. My only issue was trying to mount it on the stock PC77 pistol - the front sight blade made that impossible. I whipped-up a quick alignment tool in the machine shop (5" long, 1/2" diameter Delrin rod with 3 flats machined along the sides to clear the sensors and bottom try, pointed end to align to barrel) and was shooting within minutes. I just have to remember to reset between shots.

The loudness experiment was a wash - I'll repeat it outside, as I was getting a lot of reflected sound. I'll also use an A weighted meter next time.

Pix of the carbine here if you're interested:
http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=3866.msg37927#msg37927

JMJ

[1377x]

nice numbers!
good job!
the destoyer ex pellets weigh 7.4gr according to the info i found
anyways my guns like them also even the daisy 880

[JMJinNC]

Unless the Destroyers are different than the Destroyer EX pellets, I think they weigh 7.9 grains (per the Crosman site). If they are indeed 7.4 grain, that would explain the higher velocity.

JMJ

[1377x]

destroyers are definitely different from the destoyer ex's.
over on the old gta there was some discussion on them

[JMJinNC]

I adjusted the parallax on my scope last night, down to about 15-20m. It's a Winchester 3-9x32 and the parallax was set at about 100 yards. My wife and kids are out of town, so I was actually shooting down the length of my house into my silent trap (from the back wall of the family room, through the kitchen, hallway, and into the office). This is the kind of fun that you don't get to do often! Unnerving, in a way, but so nice to be shooting inside in air conditioned comfort versus 100% humidity outside with the heat and bugs.

I assembled my portable shooting bench and shooting rest in the family room, then set up a target at 15m in the office and adjusted the front lens so the scope was virtually parallax-free at that range (per instructions here:  http://fuzzylimey.net/projects/parallax.html   ).

Next, set up the pellet trap at 10m and shot a few rounds to see where the new scope zero was. That first shot was nerve-wracking! I was happy to see a large ragged hole develop on the paper, perhaps only 1cm in diameter for 5 shots! Adjusted the scope to zero L-R and shot another group, equally tight.

Finally, moved the trap to 15m and zeroed L-R again, and made a minor adjustment down so I'm only about 1cm high at 15m. A few 5-shot groups at about 2.5cm spread edge to edge. Not great but not bad for Crosman Destroyer EX pellets.

Wife and kids are back tomorrow, so no more indoor fun.

JMJ

[Daysailer]

When I first started my indoor,  Upstairs bedroom - door -  hall - door - other bedroom (near window),
I also had the nerves... Really concentrated on developing really safe habits, and now just
remind myself to keep with proper method and habit.  Also 5 x 5 ply covered with carpet backboard
behind my DC trap.  Over 14,000 shots....no stray holes except the edges of my clipboard
from shooting off-hand at bulls too near the edges.

....
the destoyer ex pellets weigh 7.4gr according to the info i found
anyways my guns like them also even the daisy 880

The Destroyer EX  actual weight 7.36 - 7.54gr on my scale.. My 1377's like them too.
Interesting deformation at various speeds into duct seal.

Same scale :
RWS Miesterkugeln  listed 7.0gr, actual weight 6.98 -  7.12gr
RWS Basic listed 7.0gr, acutal weight 7.0 - 7.3gr...most are 7.16 - 7.24gr
CPL 7.9, actual weight all within .1 grain.
JSB Exact Express, same as CPL
JSB Exact .20 cal 13.4gr, actual weight 13.5 - 13.8gr.
Daisy Precision Max  listed 7.8gr, actual 7.6 - 8.3gr

This is the scale I use,   very repeatable day to day tests with same pellets. 
Scale reads to .01 grain.
Only complaint, if the scale table is bumped a bit too hard, it looses its zero and
has to be power cycled to get it back....10gram calibration also useful.
http://cgi.ebay.com/DIGITAL-POCKET-BALANCE-DIAMOND-SCALE-20X0-001-GRAM-/180444390401?pt=LH_DefaultDomain_0&hash=item2a0352e401

[JMJinNC]

Daysailer - thanks for the excellent information regarding pellet weights, the scale, and your indoor range. What's my next purchase gonna be - Combro-to-PC cable or a digital scale? Tough one.

I'll correct the weight listing on my pellet database accordingly.

JMJ

[Daysailer]

Here a couple of new ones and a retest to two for your data.
tested 15 of each type, randomly taken from unsorted tins....Sorry too lazy to record and avg.

RWS Miesterkugeln 7.0....actual 6.96 - 7.06gr, 
RWS Hobby 7.0.............. actual 6.88 - 7.12gr  very few under 6.98, most 7.08
CPL  7.9........................actual 7.82 - 8.14gr, most 7.96 to 8.06
CPHP 7.9.......................actual 7.96 - 8.14gr,  only 2 out of 15 read under 8.0gr, most 8.04

My scale isnt reall high dollar, but the MK 7.0's are what i use to trust it.  I have a tin of 25
pre-sorted at 7.0...when, like today, I want to verify the scale, I re-test a few of those.