Working on Beeman Sportsman 1000 Series

[timeflys]

Greetings All, Thanks for the advise on building a vise and taking apart a springer. My Beeman Sportsman 1000 Series rifle quit working a while back. I've diagnosed it as a bum seal and have since taken the rifle apart. Several surprises. The seal is white plastic and broke into a thousand pieces. I had to use an impact driver (or impact screw driver) to get the hinge screw out. The inside of the rifle is covered in a nasty looking black grease. So here are my questions.

I've ordered a seal but it is on back order. So is this a real back ordered for now or is this really an item no longer made? The seal disintegrating, is that the way they fail or some other issue?

Is it normal to need an impact driver to remove the hinge screw? I tried the penetrating oil and heating it. Just didn't work. Should I be looking at tap and die stuff. How hard are these screws to come by?

The black gunk on the inside. I bought this gun used so it might have been from the previous owner. Then again this might be the way they are made. What do you all coat the inside of your airguns with (if anything) before reassembly?

Thanks in advance. The files section on GTA is amazing. If all this has already been answered please let me know where to find it. Thanks again.   

[Dead Springer]

I've had one of these and restored like you're doing.  I wouldn't expect that backordered parts for these would come in any time soon because it isn't a currently stocked air rifle in many places anymore.  Macarri (http://airrifleheadquarters.com/) as many parts and you can probably get a piston seal in the right configuration from him but you'll most likely have to resize it yourself because it won't be one made for this specific model.  It was a long time ago, so I don't remember any of the stats.  You'll have to do the leg work of figuring out what type of piston cap you have and what size to order yourself, he won't have any information on that for this rifle.

[Eddie_E]

If yours is one of the Spanish Norica models, you need a Vortek VS26 leather replacement kit. Does you gun say made in Spain on it anywhere?
I know it's not a leather seal, but that's the kit you need because it replaces the Norica button head with a German tapered piston head.

[Roadworthy]

Whatever you do you'll need to know the diameter of your compression tube.  You can get a close approximation by measuring the outside diameter and figuring a few thou larger.  The black gunk inside your gun probably was added by the prior owner.  The norm for new guns seems to be in many cases a brown oil.  Some people add "black tar" to damp the spring twang.  It's possible it was added to excess.  I've only had one gun requiring an impact driver to remove the pivot screw so I wouldn't say it's the norm.  Depending on the design of the gun that tension may be used to control barrel stability.  It sounds like somebody overdid it, though.

[OleTomCat]

fArcher Airguns has the seals search for BEEMANPISTONSEALS

Jim at ARH may have something similar also.

[hodg0610]

+1 on fArcher. Several parts for the Sportsman on there as I recall.

Keep us posted on how this goes please.

[timeflys]

The seal for the Beeman Sportsman 1000 Series airgun is currently on back order with Archer Airgun. Because the ad for the part hasn't been taken down I hope they will get a supply. I've seen from other posts that sometimes close enough is good enough. I'd rather not do it that way. Roadworthy says to measure the outside diameter and adding a few thousandths (inches?) extra. I don't have an intact seal to go by. I can certainly measure the compression tube. My thoughts are the other vital measurement I'll need will be the depth of the seal as it is hard plastic; hitting hard at the end of its stroke is probably what destroyed it in the first place.

Silly question but I've got to ask: If I find a suitable seal in a soft plastic, give it a try or just say no?

Thanks again for the info.

[hodg0610]

I think if you find a seal of the correct dimensions, that attaches the correct way, give it a try. I doubt it could hurt anything. If it doesn't work, you can pretty easily take it out and find something else.

[mikeyb]

I just pulled apart my Beeman RS2 Sportsman Series rifle for a lube-tune and some trigger work. This is an odd camo combo I picked up on Amazon for a little over $50. Box says RS1 Series. Rifle tube is marked RS2 Series. Trigger is the "mystery module" shown in this post ... https://www.gatewaytoairguns.org/GTA/index.php?topic=59011.msg564807#msg564807

I'm not 100% certain this has the same action as your rifle, but my piston seal is 26mm OD and this looks like an exact fit aftermarket seal for my Beeman.

https://www.customairseals.com/product/norica-piston-seal/

I also took some spring measurements.

Free length = 11.875" (not critical)
Active coils = 40
OD = 0.730"
WireDia = 0.118"

Looks like this spring cut to the maximum 40 coil length might be a good aftermarket replacement.

http://vortekproducts.com/ourstore/index.php?route=product/product&path=64_66&product_id=106

The lube-tune I just finished reduced the little twang there was to "0". The custom trigger mods I made worked better that expected. It's now at the 2.5 lb trigger pull I prefer for a hunting springer. Short light (fake) first stage take-up and a short clean break second stage to fire. Passed repeated bump tests and safety still works.

Regarding piston seal materials:

I buy OEM seals when available at a reasonable cost (IMO they should be $5 or less). When not available or too expensive I occasionally make my own piston seals.

Have acquired a small selection of polyurethane rod and tube stock close to most typical seal dimensions. Polyurethane (PUR) is a very tough material that is used to make some of the high performance aftermarket seals. My raw material cost is about $1 per inch and I can usually make 3 seals per inch of material. An electric drill, a belt sander, and a bench top drill press are the only tools needed.

The "hardness" of the polyurethane is important.
      https://en.wikipedia.org/wiki/Shore_durometer
I've used 80 Shore A piston seals for lower power springers. For magnum springers I think Shore 90 to 95 is a better choice. A seal made from 80A should work in this Beeman but 90A might last longer.

[timeflys]

Thanks for the information. I've got a couple seals on back order at ^&$@_=s. Their price is about $16 for two. I can see why you make your own. I'll see if I can't get some polyurethane - and of the correct hardness. My local hardware store has PUR washers in 1 inch and 1 & 1/2 inch. Not looking forward to trimming down 1 & 1/2 inch but I suppose it could be done. My seal seems to have been about 6 mm deep (0.233 inch) The piston is 25 mm diameter and the inside diameter of the compression tube is 27.43 mm or 1.08 inch so a diameter for the seal of 26 mm seems reasonable.

Now that I know what to ask for (polyurethane rod), I'll look into that.

Someone previously mentioned not sanding the seals being made for more than 2 seconds at a time. My guess is that getting them just right or ending up with something completely useless is fairly common?

Thanks again for the information on materials and expected cost.

[Roadworthy]

If you ordered a 26 mm seal for a 27.4 mm compression tube it will be FAR too loose.  I'd have likely gone with a 28 mm seal and trimmed it to fit.  A too loose seal will have your piston slamming against the end of the compression tube destroying your new seal and possibly your spring in the process.  Vortek sells seals in metric dimensions.  Air Rifle Headquarters sells in American dimensions.

[mikeyb]

Thanks for the information. I've got a couple seals on back order at ^&$@_=s. Their price is about $16 for two. I can see why you make your own. I'll see if I can't get some polyurethane - and of the correct hardness. My local hardware store has PUR washers in 1 inch and 1 & 1/2 inch. Not looking forward to trimming down 1 & 1/2 inch but I suppose it could be done. My seal seems to have been about 6 mm deep (0.233 inch) The piston is 25 mm diameter and the inside diameter of the compression tube is 27.43 mm or 1.08 inch so a diameter for the seal of 26 mm seems reasonable.

Now that I know what to ask for (polyurethane rod), I'll look into that.

Someone previously mentioned not sanding the seals being made for more than 2 seconds at a time. My guess is that getting them just right or ending up with something completely useless is fairly common?

Thanks again for the information on materials and expected cost.

I'm puzzled by your measurements. My Beeman piston measures 25mm in diameter. The base of the factory piston seal measures 25.6mm and the top of the piston seal, where it flares out a little, measures 26.4mm. This is consistent with the aftermarket 26mm seal shown in the link. The factory seal (with some wear) fits my compression tube snug up to the end of the cocking slot. When is is fully into the compression area the fit feels just a little tighter. I'd estimate the piston needs 2-5 lbs of force to fully seat all the way into the compression tube (with the transfer port open). This is pretty typical for most of the springers I've worked on.

If you are "sizing" a seal, you want to remove a TINY amount of material and test for fit, then repeat until you get the perfect fit. It is VERY EASY to sand TOO MUCH and end up with a loose fit. You might be able to save that seal for another springer with a smaller compression tube, but it's now worthless for your main project. Not too heartbreaking if it's a DIY seal at $0.33, but OUCH when it's a $20 (+S&H) aftermarket seal you waited many weeks to get.

Can you measure the OD of your compression tube? I'm curious to compare it with the Beeman Sportsman Series RS2 version I have.

[timeflys]

I am using a Lee dial caliper that gives me a reading in inches, then multiplying by 25.4 to get millimeters. There is probably some operator error happening; hopefully not much. My seal shattered so I don't have an old one to go by.

The inside diameter of my compression tube (and I'm having to measure from the back end of it) is 25.85 to 25.6 mm. Last time I got 27.4 - didn't happen this time.

The outside diameter of the compression tube measures 29.92 mm; close enough to 30 mm it makes me wonder.

The diameter for my piston is between 25.019 to 24.96, so 25 mm. To get that I rotate the piston, take a reading, rotate it some more, take another reading. I can easily put the piston into the compression tube. It is close but I can wiggle it around side to side just a bit.

So, this all makes me wonder if I can find some 1 inch PUR washers that are just a bit oversize. I might be in luck. Otherwise buy 1 & 1/4 inch and take 4 mm off the OD - slowly, very slowly.

Feel a bit foolish here. Good catch on the measurements. From here on out I'll measure them in the sunlight. Thanks again
 

[Eddie_E]

If it measures around 1.0236" then you can use a Vortek VS 26 leather replacement kit.

[mikeyb]

If it measures around 1.0236" then you can use a Vortek VS 26 leather replacement kit.

Looks like 26 mm is the right OD, but Vortek doesn't currently have any of those listed on its website.

Can't confirm that this is 26mm, but it sure looks right and is in stock at an almost sane price.
https://www.pyramydair.com/product/beeman-gs-1000-950-piston-seal?a=7954