1740 Target Chronograph Results

[T191032]

Well, I had a request for some "numbers", so here they are.  Let it be known, I was a bit surprised myself, though certainly not disappointed. 

Air Pistol : "1740 Target" .177 Caliber, fitted with Charles Mellon's Power Adjuster.  The stock hammer spring was in place, and I screwed the adjuster in until it was flush, or just barely inside the adjuster.  It took 3 turns to get a full shot to confirm the pistol would shoot a full-power blast of CO2. 

Pellet used : RWS Mesiterkuglen 8.2grain Wadcutter.  None pre-weighted; taken straight from the tin, same tin of pellet's I'd used to site-in the pistol with. 

Conditions : Temperature in the house was 69 degrees.  Chronograph was set up 3 feet from the muzzle.  I did not keep time between shots.  Due to two jams (wadcutters reversed with skirts going into breech first - the RWS Meisterkugelns were just a bit too hard to force the bolt closed), I had to stop and go downstairs to poke the pellets out.    I was neither trying to rush, nor take my time, just see what happens.
 
I "fudged" a bit with a couple of extra shots in two different strings; this resulted in a total shot count of 95 RWS Meisterkuglen 8.2gr Wadcutters going down the barrel.  Those extra shots were not counted in the results, however, I simply had lost count as I was picking the pellets straight from the tin and had not lined them up for a more orderly shot string as I usually would.  The CO2 powerlet was not weighed prior to shooting, only a drop of Pellgun oil applied.  The pellets were not weighed either, as noted, merely plucked straight from the tin.


String #1 :

514, 514, 511, 512, 512, 511, 515, 514, 515, 515

H - 515
L - 511
A - 513
ES - 4
SD - 1


String #2 :

516, 514, 514, 514, 514, 514, 511, 512, 509, 512

H - 516
L - 509
A - 513
ES - 7
SD - 2


String # 3 :

514, 511, 509, 510, 508, 508, 508, 507, 504, 503

H - 514
L - 503
A - 508
ES - 11
SD - 3


String #4 :

506, 503, 503, 502, 502, 499, 501, 500, 499, 498

H - 506
L - 498
A - 501
ES - 8
SD - 2


String #5 :

509, 502, 502, 502, 496, 500, 506, 505, 503, 500

H - 509
L - 496
A - 502
ES - 13
SD - 3


String #6 :

502, 508, 507, 506, 504, 500, 497, 496, 494, 501

H - 508
L - 494
A - 501
ES - 14
SD - 4


String #7 :

500, 496, 494, 490, 482, 482, 477, 474, 465, 457

H - 500
L - 457
A - 481
ES - 43
SD - 13



String #8 :

444, 432, 420, 408, 395, 379, 370, 356, 340, 316

H - 444
L - 316
A - 386
ES - 128
SD - 41


String #9 :

303, 286, 268

H - 303
L - 268
A - 285
ES - 35
SD - 17

Ok.  It is true that I should have chronographed the pistol *before* I added the power adjuster, but given the inital problems I had, I wanted to go ahead and get the adjuster added while I had the rear sight off the pistol from having re-assembling due to the factory bolt-problem.  Where things surprised me, is that I had the adjuster turned out to reduce spring tension, so I turned it into the adjuster just flush to add some.  I had room to turn in, as I could hear the spring as I added additional tension turning the adjuster farther into the body, then decided to back off to the flush position and give it a go.  I did not expect to get 95 shots out of this pistol right off like this, but I'm certainly not complaining, giving the fps "power level" it shows in the first 6 shot strings.  An easy 60 possible shots is a nice figure from a CO2 powerlet, for sure, too me anyways, as I would sometimes shoot 5 of the CAPOF Monthly Competition targets at one setting (12 pellets x 5 targets = 60 shots), so ample gas to go 10 more covers it well.

Shot # 29 and 62 were the jams (reversed pellet - skirt into breech first) that required me to stop and head downstairs to take my coated .177 rod and poke out the pellet, which was re-inserted correctly and fired.

Actual shot #41 was the 11th shot in string #4, at 502 fps.  It was deleted, as all shots are 10-shot strings.
Actual shot #71 was the 11th shot in string #7 and deleted, as the second time I lost count of string shots.

Total pellets fired were thus 95, all quality "RWS Meisterkugeln 8.2gr."

[T191032]

Second time around, different pellet.

Pistol : "1740 Target".  Again three shots were needed for the first full shot of CO2 when I began.

Pellet used : Crosman Premier Domed Hollowpoint, like you'd find at Wal-Mart.  As before, none weighed prior to shooting; however, to better sequence shooting, I pulled 10 per string to improve shooting performance and try to minimize holdups.  Only one jam (reversed w/ skirt towards breech) needed coated rod to poke back out.  No extra shots in a string this time around.

Conditions : Temperature in the house was 69 degrees.  Chronograph was set up 3 feet from the muzzle.  I did not keep time between shots.  Shooting may have went a little faster this time, thanks to setting the pellets out to be loaded between strings.  The CO2 powerlet was not weighed prior to shooting, only a drop of Pellgun oil applied.


String #1 :

518, 513, 510, 514, 487, 511, 514, 513, 509, 520

H - 520
L - 487
A - 510
ES - 33
SD - 9


String #2 :

520, 516, 515, 508, 511, 507, 518, 514, 513, 518

H - 520
L - 507
A - 514
ES - 13
SD - 4


String #3 :

519, 515, 512, 518, 510, 506, 506, 511, 500, 506

H - 519
L - 500
A - 510
ES - 19
SD - 5


String #4 :

516, 506, 511, 506, 505, 498, 494, 496, 495, 492

H - 516
L - 492
A - 501
ES - 24
SD - 8


String #5 :

509, 499, 501, 477, 498, 495, 502, 466, 498, 500

H - 509
L - 466
A - 494
ES - 43
SD - 12


String #6 :

511, 499, 505, 496, 491, 492, 484, 491, 487, 481

H - 511
L - 481
A - 493
ES - 30
SD - 9


String #7 :

489, 475, 469, 469, 450, 444, 431, 426, 410, 380

H - 489
L - 380
A - 444
ES - 109
SD - 33


String #8 :

390, 367, 355, 345, 323, 313, 299, 261, 252, 244

H - 390
L - 244
A - 314
ES - 146
SD - 50

I tried this pellet on the second go around because the tin was sitting with the RWS Meisterkuglens I'd shot in the first round of Chronograph testing when I had sited in the gun, using some of the Crosman's to round out the CO2 powerlet rather than the more costly RWS wadcutters.  Since the gun is intended primarily for punching paper, I'll probably run wadcutters to see which it may like best, but will need a "roundball" practice load too, so a cheaper alternative will be in order down the road.

[C Mellon]

Nice job. I built a 1740 stubbie with a 6" barrel for target shooting. I tuned it to 450fps after taking some wieght of the hammer. The lighter hammer keeps it on target a little better. You don't have that slam from the stike on the valve. The shorter barrel gave me less time to wiggle before the pellet exits. I got 60 shots all at 450 before it dropped off.

[T191032]

While I did not set up the chronograph, I did switch out hammer springs to a longer one.  One I had thought about using got stuck in the hammer cavity, giving me a bit of trouble for a bit, until I got it unstuck, and gun dis-assembled/re-assembled (again  ).  I put a longer spring in and threaded the adjuster in about 3 turns and set up the target and shot until things got noticeably close to running gas out.  A mere 54 shots - two RWS Meisterkuglen's to confirm the sights zero after re-attachment and the rest were Crosman RNHP (same type as used above).  Thanks to our wacky weather situation we've been having here in VA, it may be Easter Weekend, and supposed to be 80 on Sunday, but I've got the darned heat on right now, so it's about 70 in the house.

[T191032]

Well, rather than start another thread, I thought I would just add to this one.  Here is what I did today, got to do some more Chronograph testing!!  It has been put off, so today was really the day to give it a try.  Unlike in April, the AC has been in operation due to some *hot* days, but I turned it off and opened the windows instead.

"T191032 1740 Target" Chronograph Test #1
.177 Caliber, 10.1" Barrel

2011-06-02

Replaced the factory spring with a second (Ace Hardware) even lighter feeling trigger spring.
Mellon Power Adjuster with (Ace Hardware) Longer Hammer spring w/ 4 coils cut from it,
Adjuster was threaded in about 3 turns or so, to stay in the body.
Crosman Competition Wadcutter Pellets, factory spec'd 7.4 grain
Crosman Powerlet with 1 drop of Pellgun Oil
Competition Electronics ProChrono set 36" from Muzzle Brake
Temperture : 74 degrees, rose to 76 degrees. AC off, windows open.
Took 3 shots before the 4th produced a full blast of CO2.
Kept my watch by the gun, tried to shoot a shot every 30 seconds.
* Did stop for about 20 minutes [ shot 18 ] when Mom showed up for a visit.  She wanted to know what I was doing. 


Test #1

Shot one continual string of unweighed pellets using a Powerlett to check for the Velocity and Consistency.

485, 496, 499, 499, 504, 506, 498, 498, 496, 506, 503, 507, 509, 504, 503,

507, 511, 518, 504, 513, 506, 504, 506, 508, 506, 505, 515, 520, 504, 518,

509, 505, 520, 515, 516, 510, 518, 507, 514, 509, 514, 507, 512, 512, 508,

509, 508, 503, 506, 502, 512, 509, 507, 501, 494, 505, 503, 496, 508, 504,

502, 501, 497, 507, 509, 511, 502, 503, 505, 504, 505, 513, 504, 505, 502,

502, 498, 498, 501, 498, 500, 499, 493, 486, 481, 478, 471, 463, 458, 449,

437, 430, 421, 408, 398, 381, 365, 355, 318


High - 520 fps

Low - 318 fps

Average - 495 fps

Extreme spread - 202 fps

Standard Deviation - 3204? Don't know why that popped up on the screen.

Noticed that there was less "excess" Co2 being blasted out of the Muzzle brakes holes and that noise was a little less as well compared to previous shooting.

[T191032]

Followed that up with a second one. . .

"T191032 1740 Target" Chronograph Test #2
.177 Caliber, 10.1" Barrel

2011-06-02

Replaced the factory spring with a second (Ace Hardware) even lighter feeling trigger spring.
Mellon Power Adjuster with (Ace Hardware) longer hammer spring w/ 4 coils cut from it,
Adjuster was threaded in about 3 turns or so, to stay in the body.
*I turned the Adjuster in another Full Turn
Crosman Competition Wadcutter Pellets, factory spec'd 7.4 grain
Crosman Powerlet with 1 drop of Pellgun Oil
Competition Electronics ProChrono set 36" from Muzzle Brake
Temperture : 77 degrees. AC off, windows open.
Took 4 shots before the 5th produced a full blast of CO2.
Kept my watch by the gun, tried to shoot a shot every 30 seconds.
Noticed that the Adjuster turns during the shooting process.  Cocking effort was easier compared to the previous Stock spring with Adjuster turned out.


Test #2

   This test was shot using the 10-shot string sequence using a new Crosman Powerlett.

1) 519, 515, 519, 525, 526, 528, 534, 530, 526, 530

H - 534
L - 515
A - 525
ES - 19
SD - 5


2) 526, 532, 530, 527, 526, 533, 533, 534, 536, 538

H - 538
L - 526
A - 531
ES - 12
SD - 4


3) 531, 531, 530, 529, 532, 537, 533, 535, 531, 527

H - 537
L - 527
A - 531
ES - 10
SD - 2


4) 534, 529, 532, 532, 527, 530, 531, 527, 527, 529

H - 534
L - 527
A - 529
ES - 7
SD - 2


5) 530, 528, 526, 524, 524, 527, 532, 523, 523, 527

H - 532
L - 523
A - 526
ES - 9
SD - 3


6) 528, 525, 529, 527, 522, 522, 524, 519, 518, 520

H - 529
L - 518
A - 523
ES - 11
SD - 3


7) 523, 522, 521, 521, 524, 521, 519, 517, 515, 506

H - 524
L - 506
A - 518
ES - 18
SD - 5


506, 501, 494, 490, 483, 475, 466, 457, 446, 436

H - 506
L - 436
A - 475
ES - 70
SD - 23


9) 425, 412, 398, 388, 370, 349, 339, 322, 291, 285

H - 425
L - 285
A - 357
ES - 140
SD - 48


   Noticed that there was less "excess" Co2 being blasted out of the Muzzle brakes holes and that noise was a little less as well compared to previous shooting.

AND, shot the 2400KT Carbine - using Croman Comp WC, 75 shots on it's first Powerlett! (Its fitted with a Mellon Adjuster and factory hammer spring, btw)

[1377x]

good job
numbers look very consistant through the 7th string 

[tatsumi]

 :-*Great write up, does take a lot if time Getting the numbers sorted so thanks for taking the time to do all that.
What im reading is a good speed and interesting that the fps variation is roughly the same at higher room temperatures and my testing that was done in a cold room.