Need a little Tempest help

[45Bravo]

I recently picked up a first year tempest.
It shoots great, and is accurate for a springer pistol.

It shoots and cocks smooth.
Trigger is about 2 lbs, with very little creep.

Now for the questions/issue.

The first shot chronos at 395 fps with 7.4gr crosman competition wadcutters.
then after about 20 shots,, it settles down to average 308 fps+/- 4 fps.

let it sit for a couple days, and it starts at 395 again and drops back to 308 fps.

No leaks from the breach seal (toilet paper test)

So, do the springer guys out there think its a spring issue, or a piston seal issue?

Thanks.

Ian

[Stinger177]

I recently picked up a first year tempest.

So that would be a '79 model?

Nice little gun to have, especially the first Gen ones. What is the serial number of yours?

I have a Tempest that I bought around '89 or so. Although I haven't noticed your symptoms on that particular gun, I have noticed it on several others, notably my Crosman 13xx's and my Zoraki HP-01, both of which are NOT springers. Since I'm somewhat laid up with a foot injury right now, I'm planning to catch up on some gunwork. I'll put it on my list to check out my Tempest and see if it does the same thing as yours. I also have a Hurricane that I can check out as well.

That being said though, I would be interested in others comments about this anomaly. My first thought is that it had something to do with internal temperatures in that, as things warm up inside (pump tube especially) , the air pressure lessens, cold air being more dense than warm. Been wondering also if guns produce higher FPS in cold weather than in warmer. This could get technical in that one would have to document outside air temp, barometric readings, etc., but when I really start thinking about it, those could end up being minuscule factors compared to the high internal temps of air guns.

Thoughts, anyone??      Beuller,..... Beuller?

[Roadworthy]

I don't know the Tempest.  My experience leans toward a piston seal issue, though.  That one may be old enough to have a leather piston seal.  You could try some silicone oil to rejuvenate it a bit.

[Gipper]

I think you just need to write the thing off and send it to me for a proper burial!!

Good to see ya back on the forum bud.  Hope all is well with the family.

Gipper

[45Bravo]

Yes 79 model
Serial number 10576.

It doesn't have leather seals.

Shoots great I was using it to move acorns off the paved driveway one at a time at 3-10 yards. 
(I am easily entertained)


Good to be back Brian, I never left, just lurked a lot, didn’t do much airgun stuff while work and family took precedence.

Living in Houston now.

[MDriskill]

What I would try, in order:

1. Different pellets. The Tempest has a nice tapered lead-in on the breech end of the barrel, and likes ammo with large-ish skirs. Crosman pellets have quite small skirts. I really avoid them in springers generally.

2. SPRINGER HERESY ALERT: Dry fire it a couple times. I’m not kidding, it’s what the factory recommends to size/fit the piston seal to the cylinder. The seal in these is a solid slug of PTFE, not leather, no delicate “parachute” edge, and is very tough.

3. Replace the breech seal next. The fast first shot (dieseling a bit of accumulated oil/greasej, and slow subsequent shots, could both be exacerbated by leaky breech sealing.

4. If those don’t do it, might be time or a new spring and piston seal. A Tempest should be doing 400+ FPS with lighter pellets.

[Stinger177]

I shot my Tempest over the chrony this morning. FWIW, these are the results:

Cold from the garage - approx. 50 degrees F. 7.0g RWS wadcutters, Altitude 5400 ft. ASL (Denver)

First ten shots
1      399FPS
2      430
3      433
4      439
5      441
6      457
7      439
8      437
9      453
10    449

Let the gun sit for about 1/2hr. on the patio table. Temp. approx. 65 degrees F

Next ten shots
11    445
12    446
13    439
14    442
15    442
16    436
17    434
18    434
19    433
20    435

I've owned this gun since new. Have never changed a single seal. Always kept it lubed as instructed from Beeman, using the Beeman Basic Maintenance Kit.

It's easily had over 3,000 pellets through it.

I didn't bring the Hurricane for comparison.

Hope this helps.

Dennis

[45Bravo]

Yours needed 1 shot to “wake” up.

Mine goes to sleep over about 20 shots. 

[Stinger177]

I would try everything mentioned above, including Driskill's idea, before tearing into it. But if it comes to that, this is the only place I know of to get both piston and breech seals:

https://www.gunspares.co.uk/products/24546/Tempest-1979-2005/

It'll take about 4-6 weeks to get it from the UK, but I've bought a lot of parts from them with no problems.

PyramydAir has just the breech seal but it should be pretty obvious if that is the main problem.

https://www.pyramydair.com/accessories/parts/webley-parts