So, what the scoop - Todd?

Message

Plink-Panther · #1 Post by **Plink-Panther** » Wed Oct 19, 2005 9:35 pm

Are you going to buy a 2289 and mod the heck out of it or what?

we're all waiting.

Also - what fps do you typically get (or anyone) with your P3/Hw40/M2004 in the winter? Good enough performance?

Issues to be aware of? Thanks!

Will

TCooper · #2 Post by **TCooper** » Wed Oct 19, 2005 11:02 pm

Hi Plink-Panther,

I'm not sure if I'll get a 2289. I dunno if I want to get into all that pumping. The CanTire store in my area seems to be out of them right now. The urge may hit strong if I see one in a store

My HW40 lost some velocity when I last tested temperature sensitivity. When going from 70F down to 55F I think I lost around 20-25fps. The test was done with the original factory piston seal. Hmmm... I wonder if a fresh seal would do the same thing. Why are you making me do this. LOL

Okay, my 6.5 year old HW40 piston seal is finally tired. It takes about 10 shots before velocity comes up to the normal range for this pistol. When it was new I was getting around 380fps with 7.9gr Crosman Premiers. These days the velocity starts around 365fps and slowly works up to 380fps over a dozen shots. The velocity stays there for the duration of the shooting session because the seal is warm. A tired piston seal, after close to 25,000 shots. Well, I happen to have a couple of new #117 nitrile o-rings so I just installed one on the piston (3 minute task). The pistol is now in my fridge cooling off. More to come...

Todd

TCooper · #3 Post by **TCooper** » Wed Oct 19, 2005 11:55 pm

Okay, after 40 minutes in the fridge, the velocity test is done with the fresh piston seal. I removed the thermometer and the HW40 from my fridge. The thermometer said 43F, which is a couple degrees higher than I think is proper for a fridge. I rushed to my target trap and shot 5 pellets. 379,379,378,375,377.

Summary.... The HW40/P3/M2004 should be fine for shooting at temperatures down to the low 40s. Velocity doesn't seem to suffer so accuracy and POI should be the same as warmer temps. I have no idea how much colder you could go before the seals get stiff (or shrink) and velocity and accuracy become erratic.

HTH,
Todd

TCooper · #4 Post by **TCooper** » Thu Oct 20, 2005 1:01 am

Okay, more HW40 testing and more data/theory.

7.9gr Crosman Premier pellet at 43F (from fridge) = 379,379,378,375,377 - Ave = 378 fps
7.9gr Crosman Premier pellet at 73F (warm room) = 377,378,379,377,378 - Ave = 378 fps

During the above tests the pistol was placed in the 43F fridge for 40 minutes and then immediately tested. Then the pistol was allowed to rest for 40 minutes at 73F and immediately tested again (no pre-test shots). After shooting approximately 20-25 "warm-up" shots at 73F the velocity was tested once again.

7.9gr CPL at 73F = 385,386,381,385,382 ------- Ave = 384 fps
8.4gr JSB Exact at 73F = 380,383,380,380,381 - Ave = 381 fps

Summary - The HW40 does not appear to be loosing any velocity when shot at 73F or at a reduced temperature of 43F. After shooting the pistol for at least 20 shots, the seal and compression tube likely warm up a little bit and this results in an average increase of 6 fps when shooting 7.9gr Crosman Premier pellets. This small increase doesn't affect POI so it's not really an issue... but an interesting discovery

Todd

killercrow · #5 Post by **killercrow** » Thu Oct 20, 2005 2:44 am

hey, if you wanna get technical with your temperatures and whatnot, air is heavier when its cold, no? also, speed of sound is slower the colder it gets...

Plink-Panther · #6 Post by **Plink-Panther** » Thu Oct 20, 2005 7:58 am

Well thats cool to know Todd - thanks!

So if anyone asks, we can refer to your tests that there is no noticable difference in fps between room temperature (21C) and fridge temp (4-6C)

~~~~~~~~~~~~~~~~~~~~~~~
I put that tasco reddot on my 2289 using the intermounts (and two thin strips of gritty tape applied around the barrel in front of each mount to prevent the reddot from ever creeping forward) and its a fun gun to shoot.
I'm not a very good shot but it gets about 1" or 1.25" 5 shot groupings at 12m with cheapo Daisys. Add the steel breech & good pellets & a better shooter & of course the accuracy potential spikes.

I don't mind the pumping - we get stronger in the 'pecs' so it gets easier and it will help warm me up in December/January/February!

take care & thanks
~W~

TCooper · #7 Post by **TCooper** » Thu Oct 20, 2005 12:21 pm

Hi Plink-Panther - As of today, the temperature test is now on my HW40 Review.

Killercrow - The weight of the air doesn't seem to effect velocity between 43F and 73F. The same average velocity was recorded at both temps when no "warm-up/practice" shots were taken. At 73F I experienced a slight increase in velocity after the pistol was warmed up further with 25 shots. I'm guessing, but I think it might have to do with the piston seal and compression chamber warming up and possibly increasing pressure very slightly (expanded hotter air). This is only my guess.

Maybe someone with a 1377 or 2289 can do me a test. Check velocity, at room temperature, with a gun that has not be shot in hours (no warm up shooting). Then quickly shoot 15 pellets at 10 pumps each and test velocity again. Maybe 3 shots at each stage will do. Post results. Thanks muchly...

Thanks,
Todd

#8 Post by **sniper** » Thu Oct 20, 2005 12:46 pm

Hi Todd,

Your test was shooting a cold pistol in the room temperature ?

Would it make a different if the pistol was shot outdoor in the winter time, let say at about minus 6 degree celcius ? because now the pistol is cold and so does the medium.

thx.

TCooper · #9 Post by **TCooper** » Thu Oct 20, 2005 1:04 pm

Hi Sniper,

Yah, I thought about that factor too but I did the test after dark and my chrono needs light. Also, I prefer not to shoot outdoors in my neighbourhood.

My HW45 experienced a velocity drop with the same process as I used with the HW40. Factors were likely the cold seals and cold metal compression chamber. Even though the air drawn in is warm, it still chills a bit from the cold metal compression chamber. The issue that I feel is important is chilling the seals and the compression chamber. My concern was whether the cold seals would hold full compression against the cold chamber. I was mainly testing to see if seal shrinkage/stiffening would result. A shrinking and non-pliable seal might not hold full compresion and velocity might drop. If the seal functions fine, as it did in the HW40, I think it would work just as well with cold air. But that's only my guess. The first shot with the cold HW40 was still 379 fps.

When I tested my TAU-7 for "temp sensitivity" I was able to drop room temp to 55F during January. I can't get my basement that low in October.

Thanks,
Todd

wllm995 · #10 Post by **wllm995** » Thu Oct 20, 2005 3:02 pm

Todd-

That's good news, because I really enjoy shooting my P3, and it's nice to know I can shoot it thru all of the winter over here in sunny Victoria - where we golf all year round and welcome any cold and unhappy visitors from the east!