Below is an excerpt from the chapter titled "Pneumophilia". The Velocities Testing section of the book also has testing data of SEVEN stock and customized Crosman 1400's (and variants).
"While my love of classic Crosman Co2 guns runs irrationally deep and wide, that obsession does not translate to most Crosman pump models. However the Crosman 1400 (and variants thereof) exhibit a combination of style, quality and performance that hits the spot (so to speak). The 1400 is of blued steel construction, and its barrel of heavier bull-barrel configuration than any other American pump. Pumping effort also seems a bit less strenuous than other pump guns. Additionally, the pop-off valve design imparts nano-second shot-time; unfortunately it also increases trigger weight as the number of pump strokes increase. Worse yet, every Crosman 1400 Ive encountered exhibited excessive amounts of trigger creep.
Smitten with the positive attributes of the 1400 and wondering about accuracy potentials, I set about correcting the hideous trigger action. A sear-engagement plate was fashioned, resulting in a wonderfully crisp trigger-break. Though little could be done to lighten the trigger pull, the resulting super-crisp let-off is preferable to a light, creepy trigger. The (now) crisp trigger and instant shot-time (inherent to the pop-off valve) make for a very gratifying pellet launch and sharp muzzle report. No other pump-gun fires with as authoritatively sharp a POW! as a healthy Crosman 1400. The sharp report, bull-barrel and instant shot-time endow the 1400 with a pugnacious appeal all its own.
A deal was struck for two Sears J.C. Higgins variants of the Crosman 1400; one a disassembled basket-case, and both leakers. The J.C. Higgins variants sport heftier blonde stocks, white barrel spacers (instead of black), and most importantly, scope-grooved breeches. Installing the scope-grooved barrel from the basket-case rifle onto my slim-line 1400 finally allowed more serious accuracy testing, virtue of optical sights. The scoped 1400 shoots just about as well as the classic Sheridan Blue Streak; averaging 3/4 to 1 groups at fifty yards with JSB Express pellets at 650 FPS on ten pumps.
The two Sears 1400s were subsequently sent to Alan Schweitzer at AB Airguns for resealing with what he terms a power re-seal. The essence of this work is adjustment of the pump linkage to bottom-out the pump cup with every stroke and drilling of a small hole in the pump tube for slightly better air intake. So tuned, the Sears guns returned a worthwhile performance improvement of about 30 FPS more velocity on ten pumps than a stock 1400.
The heavier stock of the Sears J.C. Higgins gun compliments the relatively bull barrel of a 1400 for enhanced heft, and also allows better grip purchase for heavy pump charges. Altogether the Sears J.C. Higgins variants have a heftier feel than other American pumps, but still need help in the trigger department. Ever the glutton for punishment in the quest for performance, I couldnt resist performing the sear-engagement modification to one of the hopped-up Sears guns.
That exercise was a reminder not only of how tedious and time-consuming the trigger modification is, but also how well it returns an incredibly crisp trigger break. The modified J.C. Higgins gun groups the same as the slim-line 1400, but with a bit extra punch (virtue of the power re-seal). Approaching 700 FPS on ten pumps with 14.3 grain JSB Express pellets puts it over fifteen foot-pounds; a right respectable power level for a handy, 35 pump carbine."