by Tom Gaylord
Writing as B.B. Pelletier
Diana 27S.
This report covers:
- Velocity day
- A happy accident
- Breech seal
- No problemo!
- BB isn’t daunted
- Problemo
- BB has a backup
- HOWEVER
- What size are the seals?
- What now?
- Cocking effort
- Trigger pull
- Today’s report
- Summary
Today is Part 2 of my test of the vintage Diana 27S. From the comments to Part 1 we learned that several of you own them, but you all seem to live in Europe and the UK. This model is very rare in the U.S. Today’s report is about a failure that turned out to be a huge success!
“Oh, oh! BB’s talking like Mr. Miyagi again! Better get out the rags and car wax!”
Velocity day
I normally test velocity on Day 2 and that is exactly what I intended to do. My guess was that a .177-caliber Diana 27 should shoot around 650 f.p.s. with lighter pellets when it’s in good condition. I put five drops of Crosman Pellgunoil down the air transfer port that is located behind the barrel when it’s closed and then I shot three shots to just spread the oil around. Normally I would cock and uncock the rifle to spread the oil, but we learned in Part 1 that the 27S has an anti-beartrap device that prevents uncocking except by firing.
A happy accident
The oil proved to be a happy accident because of what happened next. The first recorded shot with an Air Arms Falcon dome went out the muzzle at 542 f.p.s. That’s a little slow but I can work with it. However, the next 5 shots went like this.
Shot…….Velocity
1………….352
2………….334
3………….345
4………….347
5………….352
Wow! This rifle is way off where I expected it to be. But remember that happy accident I mentioned with the oil? It came out as a mist on the first shot, which was a diesel. I saw oil mist shoot out the muzzle and also around the breech. Ah HA! The breech seal is weak.
Breech seal
And here is the first bit of knowledge. The breech seal did not appear to be bad. It was just a little flat, but well within tolerances for a normal o-ring seal. But when I removed it I discovered it was as hard as a rock! It was flat but also immovable — allowing compressed air to rush around it. An o-ring in the breech should push forward when compressed air gets underneath it and lifts it to seal against the breech tightly. This one wasn’t moving. As long as the breech was dry I couldn’t see the air squirting out, but that oil mist made it instantly visible.
No problemo!
Well I am the great B.B. Pelletier, and a couple months ago I ordered a huge assortment of o-rings in both SAE and metric sizes. I’ll get this little puppy back on track in no time.
Knowing that the German manufacturers had used metric o-rings, I looked through my huge assortment — only to discover that I didn’t have the size metric ring I needed. Knowledge number two is — a huge assortment of o-rings doesn’t contain rings of all sizes. Fate conspires to ensure that the size you need is not in the box! That’s the same Fate that hides one of each pair of your sox in the dryer.
BB isn’t daunted
But Fate was dealing with BB Pelletier this time and I had a second huge box of SAE o-rings, as well. I would find one that’s the perfect size and laugh at Fate who thought that, just because it isn’t labeled as metric, I wouldn’t know I had one that fit!
Problemo
Nope. Fate was laughing at me. If the o-ring was the right diameter it was made from material whose cross-section is too thin to do the job. If it was the right cross-section, it was not the right size. Ha, ha!
BB has a backup
What Fate didn’t know was B.B. has a stash of odd-sized o-rings that he has collected over the years. I brought them out and, wouldn’t you know it, those that were thick enough were the wrong size and those that were the right size were too thin.
HOWEVER
Then Fate’s prettier sister, Luck, stepped in. Because, among my collection of odd-sized o-rings, was one leather breech seal I had made years ago — probably for another Diana rifle. It wasn’t as thick as it needs to be and also was not as well-formed as I would like which is why I never used it, but it was the right diameter. So I installed it and tested the rifle again — still shooting the Falcon pellet. Here is what I got.
Shot…….Velocity
1………….686
2………….681
3………….693
4………….360
5………….367
Wow! A three-hundred f.p.s. boost — just from having a tight breech seal! But what about the last two shots? I think the leather, which was the right diameter but not the right thickness, got pushed back and flattened out too much, then started leaking air again. I could shim it up and get it to work, but I was after something more refined.
The leather seal I installed is too thin for the breech and has already flattened out after three shots. But it told me what I needed to know!
What size are the seals?
Okay, here comes knowledge number three. What size is this o-ring? When I measured it the first time in the gun, the numbers didn’t make any sense. I got a material thickness of 2.4mm with an outside diameter of 13.1mm and an inside diameter of 8.3mm. What a whacky set of numbers! Surely such o-rings don’t exist and I’m just not measuring them correctly?
Then I went to Grainger’s website. Such o-rings DO exist with those exact dimensions! Golly — this stuff really does work!
What now?
Okay, what do I do now? I could order a Diana 27 breech seal from Chambers Gunmakers, but they are currently out of stock. Even if they had one I would end up paying about seven to ten dollars for just one seal and have to wait about two weeks for it to arrive. Instead I decided to spend more money and save more by ordering the o-ring in bulk from Grainger — the same guys I bought the o-ring sets from. Each one will cost me about $1.15 this way and I should have them on Monday. Sure, I will have many more seals than I need, but Diana uses the same size seal for many of their spring-piston rifles, so what I am really doing is stocking up.
Cocking effort
I have to say this 27S cocks harder than I expected. The Diana 35 I tuned with Tune in a Tube cocked with 16 lbs. of effort. That is off-the-charts good for a Diana 35 and much lighter than this 27S. Of course the 35 barrel does measure 19 inches while the one on the 27S is about an inch shorter.
I guessed the rifle cocked with 24 lbs. of effort. The scale agreed with me when I tested it, which sounds like I tested first and then wrote about it, but I didn’t. You have to remember I have done this same test hundreds of times before, so I’m getting pretty good at guessing the effort.
Trigger pull
The two-stage trigger breaks at 1 lb. 8 oz. It’s light enough but not entirely crisp. I’m hoping some lube will sort that out.
Today’s report
This was a report that was supposed to go one way and instead went another. I learned a lot from it. Here is what I learned.
A breech seal can look okay and still be leaking air.
O-ring sets don’t contain every size of ring.
A good breech seal can add hundreds of f.p.s. to the velocity.
O-rings don’t always conform to even dimensions.
Summary
I know you machinists are laughing up your sleeves at how dumb I am, but if I don’t admit this stuff publicly there are guys who need to know it that will never find out. And, even if I am naive on the subject of o-ring sizes, who knew the right ones could boost the velocity of a low-powered airgun like a Diana 27S by over 300 f.p.s.? I sure didn’t. In the past I have seen gains of 60 and 80 f.p.s. when breech seals were changed, but today was a real eye-opener.
Will this rifle deliver the same 680 f.p.s. with Falcons when a fresh o-ring is installed? I don’t really know. I expected it to shoot around 650 f.p.s. and would be very satisfied if it ended up there. If it does the rifle is shooting where it should and all I have to do is go inside and lubricate it a little. This is going to be a good series!
Sometimes it is better to be lucky than good. Maybe good and lucky, best? My own Diana saga continues in the form of a pawnshop Winchester 450 iron sight restore to functional. Finding a front sight on an auction site, and shortly after, in response to an ad, a gentleman sent me 5 sight inserts and a front sight, plus a rear sight, that didn’t fit, sigh. Oh well. After the front sight is sorted, the rear turns up missing pieces. I didn’t examine it, since it was there, until I found a front sight. Sleuths in this blog lead to at least half of the parts the rear sight needed, the most important, elevation screw. Now I wait for the delivery from Chambers. Then on a classified site for airguns and parts, today, the whole sight turns up, so now the index spring and ball appear to be on the way here in the form of a replacement sight. So now, have spent the same on parts for the sights, as I did for the rifle, but still a steal I think. Looking forward to the sight-in and favorite pellet search. I want to continue with the search for the diopter, having never used one and this being a platform I hope to try it on. I still have the Gauntlet .22 to address, select and install a scope from my collection. Airgun fun…
MMCM13,
A peep is awesome. You are really going to like it. I wish you well on your Diana saga. I myself find it very pleasing to bring one of these old ladies back to life.
MMCM13,
Would you mind sharing the name of the classifieds airgun site where you found the whole sight today? Thanks
American Airguns Classified ads.
MMCM13,
Thank you. Ad went up and came down quickly.
Here are several options for your Diana 50 if you are still interested in a correct peep sight:
https://www.ebay.com/itm/Diopter-Diana-rear-Sight-for-11-mm-rail-Anschutz/283630465167?hash=item4209b1708f:g:eKMAAOSwt4Vdk6m~
https://www.ebay.com/itm/Sight-set-diopter-Diana-sight-adjustable-metal-item-diopter-sight-set-diopter/283621896716?hash=item42092eb20c:g:xfoAAOSw0Lldh6H8
https://www.ebay.com/itm/Diana-diopter-sight-for-Anschutz-metal-part-movement-for-adjustments-perfect/283612629907?hash=item4208a14b93:g:Wc4AAOSwMT1dep~i
Please note on the third peep sight the seller is also showing a picture of a Walther peep sight in his ad. I would clarify with the seller which peep sight he’s selling
I have looked at those, I like the one in the second link, but the overseas source gives me pause. The first link appears to have the clamp serrated piece in upside down?
The ad for the plastic base rear sight is still up. I am taking the chance that the flat base plastic based sight uses the same elevation screw and elevation indexer clicker. I figure $25 is worth the risk.
MMCM13,
I’ve bought several sights from that seller in Bulgaria. I also believe that B.B. bought a diana rear diopter sight from that seller in Bulgaria.
Yes, the “foot” on the sight in the first link is installed upside down. Easy enough to fix. Good luck
Kevin,
Yes, I bought two sights from that vendor. They arrived on time and as advertised.
B.B.
Well, all the pieces assembled and the gun all sighted in. It shoots high, the sight has to be adjusted to near as low as it will go to be on at 20 yards. I find it almost impossible to focus on the front sight. Had to install the tallest insert to get it sighted. It is a nice shooter though. Seems to prefer Crosman Premier heavy. Thanks to all for help.
B.B.,
Quite the adventure you had! 😉 I have had similar ones myself. While I have delved into O-rings in the past,.. like you,… if I had ordered a large set of SAE and metric, I would think that I would be “covered” too. I seem to recall Imperial sizes as well as Japanese? sizes too. I was going to post a link I had saved to an O-ring company, but can not seem to find it.
You may consider some specialized bonding glue. That way,… you can cut an O-ring that might have the right cross-section dimensions and downsize a larger one to work? Maybe.
Good Day to you and to all,………. Chris
Chris,
Been there, done that. Did not work for me. I tried to make an o ring to fit my Crosman 101 using a specialized kit for such at work. On to plan B.
Yes, everybody knows RidgeRunner would like to have this gal move into RRHFWA. He wants all of these old gals to move in. Fortunately Mrs. RR keeps a tight rein on Mr. RR about such things. Ah well.
“Fortunately Mrs. RR keeps a tight rein on Mr. RR about such things.”
RidgeRunner, MY wife keeps a tight rein on my about such things, too…hmm, if I were paranoid, I might think they were in secret communication at night while we are asleep, hahaha! =)~
Dave,
That very well may be. Mrs. RR sometimes claims she has trouble sleeping. She may be slipping out to communicate with your wife.
BB
Very gratifying when you solve a problem through diligent troubleshooting.
Those three shots may have not only compressed the seal but pushed out the ragged edges and prevented a compete seal contact also. And that lube probably helped to up the FPS some.
I think we all talked about seals years ago. I mentioned using talcum powder on car doors to find air leaks as an example. A clean seal area void of talcum means the door did not contact the seal when ‘slowly’ closed just enough to latch. Slamming it shut would compress the seal and allow the leaking area to make contact it would not maintain once the slamming force was removed. A false impression. It may work with breach seals.
Also, penetrating oil may? swell up a leather seal. Works great on the dried out cup seal on my Harleys carburetor accelerator pump.
I used the word diligent because a problem can always be solved if you don’t give up looking for the cause.
We had a false engine fire cockpit light that plagued a particular DC-9 aircraft. Needless to say it really disturbed a lot of pilots. They kept replacing the fire detection loops and it kept returning. When it came to my airport. I reviewed the history decided it was not a faulty fire loop and looked in other places.
I started checking out the connection point on the aircraft with a multimeter and started shaking things. Sure enough an intermittent open circuit showed up inside. Don’t give up, don’t keep replacing a part you don’t know for sure is the cause and hope it goes away.
Most problems can be solved by simply observing the symptoms, as you did with the oil spray, and narrowing it down to the most probable cause before you ever look for it. This seal was kind of obvious but in other situations your troubleshooting should amount to nothing more than verifying it was the cause or eliminating it as the cause and pressing on to the next possible cause.
Ripping things apart hopping you find something wrong is very unprofessional. But one thing is for sure, you need to know how something works before you try to figure out what may be preventing it from working. If you don’t …. take it to a professional. You may not even recognize the cause after ripping it apart. Advice from an old mechanic. This is just a general rule for troubleshooting anything. Not strictly for airguns..
Bob M
Darn bad luck BB, I could have added a whole boatload of o-rings for you. Just did not think of it. I once had the same problem and ended up ordering 1000 of that approximate size o-ring from China. Took a month to get here but I’m pretty sure I won’t run out. And it turns out to fit quite a lot of breeches =-)
So yeah machinists will laugh at these antics, but I think most people who tinker with airguns (including me) are dependent on just ordering the right bits. And only out of sheer desperation will try to make something ourselves.
Can’t wait for the next installment, if it is any like my life with airguns it turns out it is something else too.
Best regards,
Carel
Carel,
At first I thought the whole day was blown and I had to move to a different subject. Then it dawned on me that this is EXACTLY what needs to be discussed. It was a big blessing in disguise.
And I will now have a boatload of breech seals for vintage Dianas! A second blessing! 😉
B.B.
“…this is EXACTLY what needs to be discussed.”
Amen to that, B.B.! And this bit about Fate and Luck cracked me up:
“Then Fate’s prettier sister, Luck, stepped in.”
Thanks, man, I needed a good laugh today!
That bit about Fate and Luck reminded me of Wisdom.
And yes, it hard to say who these type of reports will assist; even after years of reading your blog, I would NEVER have guessed you could get a 300 fps increase from a seal change. *shrugs*
Knowledge is cool, Wisdom even better. =>
Dave,
If you have watched “The Shack” you have seen Wisdom interacting with the lead character. It’s funny when it’s someone else. Not as funny when it’s the guy in the mirror.
Just wait until you read Monday’s report! I laughed until I cried. 😉
B.B.
Off topic.
When is the Airgun Show in Texas this year? Hope to locate a 3rd variant Crosman 160. Also, sell some extra guns. Sold some over the internet, but guns I thought would sell, no luck. Tried selling a S&W 79G, but maybe asked too much. I’d rather trade, anyway for something.
Jonah,
I think it will be the third Saturday in June. This year that’s June 20.
Maybe we can talk about your 79G. I might have something you would like.
B.B.
Might should talk about this outside of blog.
lroach1@hotmail.com
BB
That rant above on troubleshooting was not directed at you. Heck, you are the last person on earth I would ever try to tell how to fix airguns. I just took the opportunity to pass along information I acquired over the years on troubleshooting to readers that may help them out some day.
Bob M
BB ,
On Diana springers . There are two sizes of breech seals. RIFLE = 8×2.5 mm PISTOL =7×2.5mm . From most kits I have seen NAPA . Harbor Freight , etc. these are not included . Metric o rings are sized by the ID and Diameter . Metric orings are simple a 10mm x 3mm , is 10mm on the ID and 3mm diameter. which makes it 16mm on the OD . The 10x3mm oring is the breech seal for a FWB124 .
For non machinist folks ID = Inside diamaeter
OD = outside diameter , also referred to as the major size .
Hopefully this helps out .
Gene
Gene,
That does help a lot! Thank you,
B.B.
speaking of FWB 124/27: to BB and others:I need knowledge!! I’m sitting, looking at one (not mine) marked sport 127,cal.5.5/.22,w sling swivels, little beeman 40 scope, all vg/excellent condition — won’t shoot pellets (assume seals gone from many years in gun case) cocks easy BUT no way it is 22 cal. bbl shows FWB and obendorf /N marking and 177 pellet very tight fit. What Gives?? who do I recommend for rebuild? sorry for interuption, but few air gunners here any more!
BB,
Interesting but puzzling results but I’m sure you will get to the bottom of this 27S. I think you may well get back near the high 600’s with those pellets. That is what a healthy, standard 27 should achieve in .177. The rifle may have a strong spring in there if cocking effort is anything to go by. The 300 fps drop due to the expired breech seal is shocking. Never heard of anything like those sort of figures. If I was a betting man I’d maybe go with some diesel assistance with the high velocity figures but thats still a huge drop for a defective breech seal.
Looking forward to the next installment.
Regards,
Drew
Bob M ,
Good advice , most people just jump in without understanding how it is supposed to function . If You observe things and use logic problems can be solved , patience is key . I was a field supervisor for 6 years and most problems were items missed by people in a hurry or Trouble guessing , not troubleshooting.
Gene
Gene
Until I joined the Navy and received training in aviation maintenance I had no idea that there was a procedure to follow to identify the cause of a problem and correct it. I remember thinking how I can use it to fix just about anything.
We had to figure out what could possibly cause the problem and narrow it down to one or two possibilities just using maintenance manuals and diagrams. We then would go out to the aircraft and ‘visually’ verify it or eliminate any other possible causes we came up with till we found the right cause of the problem. All we could use was a flashlight and tools to open any access panels to inspect.
Experience eventually helps a lot.
For anybody who may be concerned about aircraft safety, everything done to repair an aircraft is signed off in the aircraft log book right next to the pilots description of the problem and it must contain the exact reference to the aircraft maintenance manual that you followed to fix it and you better have a copy of it with you if an FAA inspector finds you fixing an aircraft. Deadly serious stuff.
Bob M
BB
Fate hates people who pin dirty socks together with a safety pin.
Deck
Decksniper,
Another proven solution for single males is NYLON Laundry bags!
shootski
Did a search to see if the use of Marvel Mystery Oil instead of standard pellgun oil had ever been discussed in the blog, but found no references. So, what about using MMO on our airguns; yea, nay, or maybe?
Basil,
I have no clue.
B.B.
Gents, I have used Marvel Mystery Oil to “unstick” TWO stuck pistons in a Yamaha 400 that had been sitting outside for years (by previous owner, not me); hence, it might have some use in unsticking some stubborn old airgun parts without damaging them. =>
Thedavemyster,
One more to add to the Quiver:
https://seafoamsales.com/product/deep-creep-penetrating-oil/
Some also recommend it for carbon ring cleaning in powder burners.
shootski
Shootski
You just reminded me, I need to get some highly recommended Seafoam Trans Tune to clear up an automatic transmission problem. Overdrive clutch is stuck in engage and giving hard shifts and bucking. Stuck solenoid or clogged filter. Sounds like a good company.
Well, since we have already gone off topic…
I have noticed that Umarex is trying to get a big jump on the Shot Show this year with the release of their AirSaber. It seems that all the dealers have them in stock and most of the reviewers are demonstrating them already. With the low price they just may have a winner. The only question left is will they hold up in the field. Time will tell.
I have also noticed that Umarex seems to be paying attention to the US market more and more. They are bringing out airguns that seem to be worth owning. Our options are increasing so fast it is hard to keep up with them.
B.B.,
A great source for O-Rings: https://www.theoringstore.com/store/
They also have good educational and informational section(s) in everything you never knew about O-Rings and other seals.
I also use a right sized thin piece of tissue paper over breeches/receivers and other points of potential leakage to detect even tiny puffs of air. An additional trick for leakage point hunting, especially in PCP, is various latex sheets or tubes cut from toy balloons or other similar products (think non- ribbed or lubricated) used in conjunction with rubber bands and/or stretchy tape can help detect those slow leaks.
shootski
shootski,
Thank you. That’s a good resource.
B.B.
Shootski,
That is the one I was thinking of. Re-saved just in case I did delete the other saved bookmark.
Thanks,….. Chris
I really like opening the blog when it is ‘historical airgun’ day!
The older, simpler, airguns are my favorites. But as BB has pointed out before; even though they may seem to be, old springers aren’t really that simple!
The ultimate idea is fun and the most fun that I have is with an airgun that is easy to operate and hits what I am aiming at. (whether it’s paper, spinners, or soda cans (but i am fresh out of Necco wafers))
Lately, I’m having a great time. And this blog, with BB and all of the people that comment on it, increases my knowledge, which increases my fun! It’s a win-win!
A big thank you to you all.
Bill
B.B.
The part of this blog about O-rings is right on time for me. During the process of installing a regulator into the Diana bandit I had a leak down after reassembly. With soapy water I found it was leaking around the pressure gauge. I figured out that teflon tape does not work on this problem. Took out the O-ring that was not sealing and found nothing close to a match in a multi size set from Northern tool. What I ended up doing was to turn the original O-ring over and try it that way. Two days later (fingers crossed) it is holding air. We will see how long that fix works for.
Gerald
Participant,
Interesting. I would expect that if the gauge was sealed at the stem end (O-ring) and leaked,… then Teflon tape at the threads would accomplish the same thing. I am not sure what to make of your findings,…. but very happy for you that what you did is working.
Chris
Chris USA,
Thank you for the opening Chris!
Neither thread lockers/sealers nor Teflon® (aka plumber’s tape) tape is approved for HpA sealing by the CGA (Compressed Gas Association) but works for low pressure fluids and occasionally (for a time) for very low pressure (under 40psi at 70°) gas applications. The pressures we are dealing with are classified as: Very High Pressure in many countries and mishandling can be deadly.
shootski
Shootski,
What?,….. you are?,.. like?,.. holding back on us? Like,… you (need?) an “opening”? 😉 LOL!
I was (not) aware of that. I respect the pressures we as PCP shooter’s deal with.
So?,… I would gather from your comment that O-rings are the preferred method of high pressure air,.. sealing. Lesson learned,…. do not use “plumbers tape” and expect it to work in a PCP.
As always,… thank you for your seemingly (endless?) insight,……. Chris
Chris USA,
It may Not Be that it doesn’t work, but rather that CGA believes it works too well. See my response to Mike below. I’m going to see if I can find an answer to the WHY behind it. Maybe someone else in the readership might know the facts.
shootski
Shootski,
Would this tape be acceptable? It claims 10,000 PSI;.0035 mil thick, tolerates -450 to +500 degrees https://www.hardwareandtools.com/william-harvey-017065-pipe-seal-tape-ptfe-1-2×260-elga-6823.html
Mike
Mike in Atl,
I responded to your post about an hour ago Mike but the post isn’t here! I’ll try again. I clicked on your link to check out the tape and got a site licences alert…so I avoid going to sites that do/cause that to happen. I’m no EXPERT but have informed myself with CGA information when I first got into bulk CO2 & PCPs back in the early 1990s. As a guess, and only a guess, I suspect that the use of tape may defeat the partial V grooves that (some) fabricators cut perpendicularly to the fitting threads to prevent an Instant decompression if someone tries to remove a pressurized fitting.
I will say those are some impressive specifications!
I don’t think I’ll ever find myself shooting in anything close to those temperature extremes!
I have seen 141°F and less than -65°F…been there done that, no thank you on future opportunities!
shootski
Shootski,
Here is another link perhaps you can see https://www.oatey.com/ASSETS/DOCUMENTS/ITEMS/EN/Yellow_Gas_Line_Tape.pdf a pdf of what appears to be the same product with a different name. I came upon this product in another airgun site where they were talking about sealing the foster fitting, also suggested was this seal but it seams to max at 3000 psi https://www.gsasupplyco.com/collections/pipe-thread-sealant/products/pls-2-pipe-thread-and-gasket-sealer
Your thoughts, and anyone else who knows about this are well welcomed.
Mike
BB,
I’m curious about why you used Pellgunoil instead of silicone oil in the compression chamber. Is this gun low enough in compression that the hydrocarbons in the Pellgunoil just aren’t likely to explode? Sorry, but I can’t remember the term for violent dieseling. Also, do you think soaking the breech seal in Transmission Seal Reconditioner would soften it any?
Half
Half.
That’s it exactly. The term for violent dieseling is detonation and these guns don’t do that. They do diesel, which all spring guns over about 550-600 f.p.s. do.
B.B.
Half,
Sorry, I forgot to answer the other question. Would ATF sealant work? Yes, but it only works on the surface of an o-ring and I wanted supple rings all the way through.
B.B.
B.B.,
At Shot Show check out the Ventus and VentusX systems by Trigicon if they have any working examples! They are Doppler LIDAR systems that read the wind at 5 different distances. The price of the LIDAR systems have recently dropped by an order of magnitude so they will be in the Prosumer price range soon (this year) and the consumer range in a few more years.
shootski
shootski,
I will if I can.
B.B.
B.B. & Readership,
Mike in Atl, Chris USA and I have started an Off Topic exchange about leaks after Participant discussed his O-Ring issue on the pressure indicator on his Diana Bandit. I posted about not using Teflon® (PTFE) Tape; aka Plumber’s Tape on HpA fittings to seal them. I promised to do some research and here are the early Internet results: Unknown sources saying it is a No, No and other sites saying it is only a thread lubricating substance to allow tightening threaded pipes enough to be leak free. Most of the post are about pipes, plumbing and hydraulics/pneumatics. None of those pipes/fittings fall into the Very or Ultra High Pressure pneumatics arena. I did find this link: https://www.hydraulicspneumatics.com/technologies/fittings-couplings/article/21887858/your-connection-is-only-as-good-as-its-oring which I found an interesting read. It still isn’t about the kind of pressures we are dealing with!
Shootski,
This does lean to a blog about high pressure air guns and the the things to think about.
Most airguns do not need to be tested, as scuba tanks do needing to have a hydrostatic test from time to time.
But airguns after a period of about 10 years could become possibly dangerous as the air tube may become weak or brittle. An air tube breaking at 3000 psi could be a life changing experience.
Just some thoughts.
Mike
Mike in Atl,
You are correct to be concerned but it depends on who you buy your PCPs from. The large US, UK, and European manufacturers do adequate testing because of liability concerns. The problem is guns from other sources to include small botique builders. Not all of them do what my favorite small shop builder does:
“To pressure test airgun reservoirs I built this test cell in 1994, and with minor modifications it still works today. The ram of the hydraulic jack is removed and the pressure passage is plugged. The pressure is tapped off the side of the pump with a flex hose to compensate for different reservoir lengths. The area where the ram once was becomes a reservoir for the soluble oil. I use soluble oil because the eventual drips and spills are so much easier to clean up.
The reservoirs I use are good to 9000 psi before yield, but you don’t test every gun to where you damage it. I pressurize the gun to 6000 psi, which is twice its normal working pressure, and hold it there for 24 hours; if there’s no pressure drop in that time then it passes.” Unless you know, or can reliably find out, your builder does what Dennis Quackenbush does to test his reservoirs you might look elsewhere. I don’t think the number of fill/empty cycles of our steel air tubes is really going to work harden them. The steel SCUBA tanks are often still serviceable after 60+ years of hard use that airguns don’t see. On the other hand some the Aluminum SCUBA cylinders have had significant issues early and substantially shorter Service Life. The Carbon Fiber 4500PSI cylinders have a 15year Service Life (USA) that can now be extended with proper testing to 30 years. The DOT (USA) does not regulate any tube/cylinder 2″ or smaller in diameter since the risk is not deemed severe.
Miss application of fittings, hoses and other pressure vessel accessories is a big concern. For example, I have seen a number of 3,000-4,500PSI air compressors and fill stations using Foster® fitting knockoffs or actual Foster® fittings but not rated for those pressures. There are markings that indicate the pressure ratings for the QD fittings that are a critical piece of knowledge for users/buyers. Lot’s more to know but this is a post and not a blog!
shootski
Shootski,
Interesting topic. I guess that it boils down to what was used at time of manufacture.
I can say 100% that I did use standard Teflon tape on the male Foster fitting on the Maximus (upon re-installation) when the fitting was leaking air recently.
When I put the regulator in, the gauge had to be pulled. I am pretty sure I would have used the tape there as well,…. but can not recall if there was an O-ring at the stem end,… or not. At any rate,… everything is holding air just fine.
Chris
Shootski,
I seem to (have not) downloaded a PDF of the Maximus,… but did the M-rod. There is a female/male fitting at the gauge that (does) have an O-ring at the stem (male) end. Then,… the gauge screws into that. There is no O-ring shown there.
Just some added insight on the topic.
Chris
Shootski,
Thanks for your time in answering, I think my original thought came from this blog; /blog/2017/03/do-pressure-vessels-become-unsafe-over-time/
A quote from B.B. on that blog; “Some companies, such as Feinwerkbau, say their removable air cylinders must be replaced after a certain time, like 20 years. The date of the initial pressure test is stamped into the body of the tank, and that starts the clock.”
Thanks
Mike
Mike In Atl,
I have read that blog of B.B.’s again as well as in the past and it is up to his usual high standards. I will say that many of the comments are correct, incorrect, dated, or not to the point your system or Airgun requires.
I will say again and again that there are sources that everyone who works with compressed gases should be very familiar with, one of which (for folks in the USA and Canada) is: https://www.cganet.com/
Why, just a look at their home page shows one of interest to users of CO2 dated November 2019:
https://portal.cganet.com/Publication/Details.aspx?id=G-6.7
This is an example of the constantly changing information available to the readership that a Blog by B.B. or comments by readers like me and others just can’t hope to equal! Yes, common sense is a good first step but common sense tells me to keep informed from the SOURCE when something could potentially severely injury or cost me, family, friends, and fellow shooters their lives.
Shootski
Shootski,
That seems kinda industrial strength users of co2, the link wanted money or for me to setup an account with them, looked around and found the AIGA 074/11 document which seems to be based on the CGA G-6.7 from 2009 – Aisa version.
Kind of deep but a lot of good information it can be seen over here http://asiaiga.org/uploaded_docs/AIGA%20074_11%20Safe%20handling%20of%20CO2%20containers%20that%20have%20lost%20pressure_Reformated%20Jan%2012.pdf
Thanks again,
Mike
Shootski,
Good info and lesson learned. Thankfully not the hard way. do not improvise with high pressure components.
Gerald
Geo,
I just watched the JSB Hades/Red Wolf .25 pellet review (link) you posted a few days ago. First,.. I was not aware that they had come out with the .25’s yet. Me = 🙂 Second,.. it was the first video I have seen from Baker. Not bad, but needs some work.
He mentioned that he tried using the Pelletgage to size check the heads and found them all under the lowest sized hole. Mmmm? However,… the results spoke for themselves. Sub MOA at 50 yards.
Overall,… impressed. I will have to get a tin of them to try in the .25 Red Wolf.
As always,… thanks for staying on top of the latest and posting relevant videos.
Chris
Chris USA,
I got snowed in for the last few days so I did some chrony testing on the LGU.
Thought I would give you the results and tell you once again that I am very happy with this rifle.
I’d like to give you some accuracy details too, but the reticle on my scope twisted off level while I was doing the chrony work.
I guess I’m going to find out how good the ‘lifetime limited warranty’ is on Hawke scopes.
Thanks again,
Randy
LGU .22 cal 18″ off chrony
jsb jsb jsb jsb rws hobby
shot # 18.13 gr 15.89 gr 14.35 gr 13.43 gr 11.9 gr
1 536.6 574.7 598.8 620.4 660.1
2 538.8 576.9 605.2 614.4 664.3
3 534.6 580.7 608.1 620.0 664.3
4 533.8 583.6 603.6 617.8 663.2
5 535.0 576.7 609.6 617.0 664.0
6 533.1 574.1 608.5 622.1 666.6
7 536.0 577.1 605.6 627.4 665.2
8 536.1 572.9 601.0 613.8 665.1
9 539.1 584.8 608.7 624.8 664.0
10 539.7 583.7 607.9 621.0 665.9
average 536.3 578.5 605.7 619.9 664.3
high 539.7 584.8 609.6 627.4 666.6
low 533.1 572.9 598.8 613.8 660.1
spread 6.6 11.9 10.8 13.6 6.5
std dev 2.3 4.4 3.6 4.3 1.8
fpe 11.6 11.8 11.7 11.5 11.7
Randy,
Very happy you got to collect some hard data on it. I do believe I used the 15.89’s,… but may have tried the others as well (for accuracy). You (should?) have some notes on it from what I sent with it.
I am very happy that you are still happy. 🙂 It is a fine, fine shooter for sure.
Chris
B.B.,
I was responding to Kansas Heat a bit ago and mentioned past data that I collected.
For a few years now,… I find that I am (lacking??) in my data collection methodology,… or, maybe not? I would consider myself to be a bit obsessive on detail,… so this is even a surprise for me to some degree.
“Lacking”?,… well, when looking back, I think I could have done a better job. Generally,.. I will chrony and shoot a variety of pellets and narrow down from there. Repeat to verify. Data gathered,… I decide the best pellet and stick with it. Still,.. you might have something to further ponder?
So?,.. what is my point? Well,… if you have anything to offer on the “finer” points of data collection,… usage,… interpretation,….. then that might be a good blog topic.
Chris
Chris USA,
Yet another opening Chris!!!! Lol!
To get you started while B.B. thinks things over and is busy with Shot Show….
http://www.impactdatabooks.com/My_First_Book_s/136.htm
Start reading here and then if you like the information gained move to the rest of their site to see some stuff! Remember you don’t need to buy the stuff from them!!!
But you may want to.
shootski
Shootski,
LOL! 😉 I will save and review. And,… I will say,… that you seem to have “this” particular topic down very well. Maybe?,.. as a regular (skilled) contributor to the blog,… you could offer some further insights? To put it rather bluntly,… a guest blog.
On that,… BB does very thorough testing (and) offers many solutions/explanations/theories to his findings.
Your over and above efforts (if enacted) would alleviate BB of an added task and yet at the same time,…. offer the readers here some insightful perspective to data gathering and interpretation.
Something to ponder as you are charging down the “extreme” (IE: almost certain death) slopes. 😉
Chris
Shootski,
Just did a (very) quick review of your link. Looks (very) good and looks to be something I will spend some time on.
Again,…. ditto on my previous comment.
Chris
Geo
I responded here to your reply you posted on the other report.
To start with I broke my phone at the begining of the week. Got a new one the next day. Been getting it all set up. And got that 95 Mustang GTS and been messing with it straightening up some stuff on it I dont like. And the wife is off this week so we had stuff to do. And been seeing the daughter and the baby. So just been one of those weeks. But yep everything is ok as much as can be. And thanks for asking.
And yep have checked out that full auto PCP already. I just wonder how reliable it is. That’s the problem I have been finding with the true semi auto pellet air guns. Reliability.
GF1,
Glad you hear that everything is okay and that you’ve just been really busy. You are such a regular commenter that I was concerned when I didn’t see any posts from you for several days. Yeah, when you become so dependent on those cell phones, when one breaks your whole world it turned upside down.
Geo
Geo
The problem now is I gave my oldest daughter my laptop a year or so ago. So my cell phone is all I have. And yep I do depend on my cell phone. Got to much going on to be tied down by a laptop nowadays. Always moving it seems. Guess I’m too use to the convenience of having access wherever I’m at. I dont see myself turning back anytime soon.
Milk ,
It is a 127 that has been re-barreled at some point in its life . Yes the piston seal is bad , do not dry fire this rifle . We can rebuild it here at Air Venturi or David Slade at the Airgunwerks in TN . If You send it in the bill is about $100 parts and labor for just the seals and about $130 with a new mainspring . AV phone # 888-262-4867 or Airgunwerks = 931-933-5861. I recommend this rifle is professionally rebuilt , there is massive pre load on these springs.
Gene
Gene,
Thanks for that.
Milk,
That would have been my recommendation, as well. Yes, this is a re-barreled 127. Same gun, different barrel.
B.B.
thanks,Gene! I know better than to tear into springers of any size/quality. certainly don’t need another, BUT what would be a good offer/price for the gun (before rebuild) since I assume mismatched bbl. gun would not interest real collectors? Read much of B.B’s early 124 articles– seems it would fit right in with my RWS 36,45,48 style guns.
Milk ,
The gun has value as a shooter , probably $200 as it sits and about $300 to $350 after rebuild . Keep it and enjoy it . I would keep it and enjoy it , they are the best break-barrel spring gun ever made – Bar None !