Author Topic: Any one ever heard of the Dynamic PCP air rifle? (Read 57520 times - 1 votes)
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kingrude1 · « **Reply #440 on:** July 29, 2018, 03:57:55 PM »

Quote from: jarmstrong on July 29, 2018, 03:49:10 PM

Why do we use standard size o-ring in a metric base airgun

If you know the correct sizes, then spit it out, if not you are just here to tell us how wrong we are, which is of no help to anyone.

Rat Sniper (AKA: PaulT58) · « **Reply #441 on:** July 29, 2018, 04:32:27 PM »

Quote from: kingrude1 on July 29, 2018, 03:46:48 PM

Update: After muching swearing and promising to throw this rifle in the river, I settled down, went back and took it all apart slowly inspecting everything carefully. I some how got the airtube turned around and had the vent hole down stream DUH. Removed and replaced all o rings again, carefully cleaning before installing. Put it back together "RIGHT" this time, aired it up and it is holding air, fingers crossed that I don't have a leak.

LOL! I did the same thing! That small little air vent hole is hard to see and it’s easy to put it together backwards. I was thinking about marking the breech end somehow so I didn’t do it again. Glad you got it figured out and hopefully it will hold air. Mine is still holding air with the 116 o-rings.

nervoustrigger · « **Reply #442 on:** July 29, 2018, 04:37:44 PM »

Quote from: jarmstrong on July 29, 2018, 03:49:10 PM

Why do we use standard size o-ring in a metric base airgun

The grooves were machined too deep. Apparently the manufacturer knew there was a problem because some people found shim material under their O-rings. So if the original O-rings were a 2mm cross section (0.079"), trying the nearest -1xx size (0.103") makes perfect sense.

jarmstrong · « **Reply #443 on:** July 29, 2018, 04:47:03 PM »

Quote from: kingrude1 on July 29, 2018, 03:57:55 PM

Quote from: jarmstrong on July 29, 2018, 03:49:10 PM
Why do we use standard size o-ring in a metric base airgun
If you know the correct sizes, then spit it out, if not you are just here to tell us how wrong we are, which is of no help to anyone.

I just asked a question,.
If I owned one ,I would get my calipers out and measure the groove size and the air tube ID and buy o-rings to fit

Success is its own reward. best of luck in your ventures

jarmstrong · « **Reply #444 on:** July 29, 2018, 04:49:11 PM »

Quote from: nervoustrigger on July 29, 2018, 04:37:44 PM

Quote from: jarmstrong on July 29, 2018, 03:49:10 PM
Why do we use standard size o-ring in a metric base airgun

The grooves were machined too deep. Apparently the manufacturer knew there was a problem because some people found shim material under their O-rings. So if the original O-rings were a 2mm cross section (0.079"), trying the nearest -1xx size (0.103") makes perfect sense.

Ah, we have a quality control problem, I see now. Thank you

kingrude1 · « **Reply #445 on:** July 30, 2018, 02:49:24 PM »

Well I am still not there yet stopping the air leak on my Dar.25, slowed it considerably, leaked down to 100 bar overnight. Guess I will wait on my other one rings before trying again.

Wayne52 · « **Reply #446 on:** July 30, 2018, 02:57:19 PM »

David I had mine out this morning, put about 60 rounds through it, I need to buy me another tin of the JSB MKII's and do some shooting with them, just to see how accurate the DAR can be at a distance.

Wayne52 · « **Reply #447 on:** July 30, 2018, 03:06:20 PM »

After my last post here I decided to check the DAR17 since I filled it out of the box and chronied it then topped it off, it held the air for a couple days (I didn't check it yesterday though) so it's time to put O rings in it for sure, I didn't think it would last.

Taso1000 · « **Reply #448 on:** July 30, 2018, 08:07:04 PM »

Would cutting the oring groove wider allow you to use a larger cross section oring to compensate for the too deep groove cut? It sounds like there's not enough oring cross section to bridge the gap. The depth of the groove should be less than the width so that the oring is forced out against the cylinder.

The way I understand how orings are supposed to work is that they conform via pressure to and seal both surfaces. I have attached a picture of various examples.

I think example (b) is the correct way. A too soft oring will look like example (c) and (d). To hard an oring will not conform and leak. I have read that 70 duro is recommended for 3000 psi and 90 duro for 4500 psi.

I initially thought about some kind of backer to take up some of the loose inside diameter. Like a shallow piston ring. It may take up enough space to initiate the seal. I don't know if the seal will last as pressure drops.

There are members with more experience in this area than me but I had some ideas to share.

Thanks,

Taso

tracker1955 · « **Reply #449 on:** July 30, 2018, 09:13:32 PM »

I went to Nashville rubber and gasket after work today to buy new o-rings but they didn't have 90 duro so went back to the o-ring store online and purchased some buna-n 90 duro, some urethane 90 duro and some square 70 duro rings. I thought the square 70 duro rings may help since they have more surface area in contact with the air tube. Will try the buna 90's first as Wayne is using them now and they have been holding air ok. New rings should come usps Wednesday, just want to shoot the DAR again, chrony and check pellets.

Wayne52 · « **Reply #450 on:** July 31, 2018, 01:02:24 AM »

I forgot to mention that the o rings that I got out of the 177 had lost their elasticity and were more like putty than good rubber. I'm thinking that possibly there were still oils in the gun that might have caused this that were originally used for machining and they were breaking down the o rings. I did clean out the airtube really good before reassembly. I'm pretty convinced that the 90 duro's will work out just fine. I also had to remove some of that shimming material on the o ring on the o ring on the probe assembly on the 177 too but that was the only one that they did like that on the 177, the 25 cal had them all shimmed like that.

Gertrude · « **Reply #451 on:** July 31, 2018, 10:06:05 AM »

Can anyone tell me bow to remove.the pin between the bolt and hammer ?
Is it an Allen head ? Or a roll pin ?
Having some trouble getting the bolt and hammer removed from monoblock.
Any pics.would be great
Thanks

Wayne52 · « **Reply #452 on:** July 31, 2018, 01:43:01 PM »

Ron if you're talking about the pin for the sear catch, there's an allen bolt on the back of the hammer that holds it in there.

TheSaint · « **Reply #453 on:** July 31, 2018, 01:50:48 PM »

Are you trying to remove the hammer? If so, it's an Allen head bolt in the middle of the rear of the hammer. You've got to remove the trigger assembly to get everything out. The hammer sits in a separate, slotted tube that you have to slide into the correct position to remove the sear catch pin.

My granddaughter is coming over this weekend to show me how to post pictures.

Gertrude · « **Reply #454 on:** July 31, 2018, 04:51:30 PM »

Thanks for the replies.
I am not referring to the Sear Catch Pin. (Mine actually fell out without having to loosen the Allen screw in the rear of the hammer 😒).
The pin I am referring to attaches into the rear body section of the brass bolt itself.
There is a second hole through the hammer, (that is forward of the Sear Catch Pin hole).
When positioned properly, this pin that is in the brass bolt is visible.
It would appear to me that this might be a "Cocking Pin" (?), that engages the hammer, when the bolt cycles back upon cocking... Thus allowing the Sear Catch Pin to engage the Trigger Sear.

I can see this pin in the brass Bolt. The forward "shoulder" of the hammer will not pass by the end/tip of this pin, thus preventing removal of the hammer from the mono block tube it slides in.

I am currently on my phone and can not attach a pic.
I will try to attach a pic when I get to my computer.

Gertrude · « **Reply #455 on:** July 31, 2018, 05:06:11 PM »

Oops,
Nevermind, ... I just got it out.
It IS a threaded pin with an Allen head.
Thanks

Wayne52 · « **Reply #456 on:** July 31, 2018, 05:26:36 PM »

Ron I use an Optivisor that I have from the electronics business and I use it on airguns often, very nice magnification along with a flash light I can't do without it. It is really nice for my old vernier calipers too, I need to break down and buy another dial calipers, heck they're cheap at Harbor Freight now.

tracker1955 · « **Reply #457 on:** July 31, 2018, 07:24:03 PM »

Thought I'd give one more go at trying to make the regulator seal, took the o-ring out of the grove and then wrapped several winds of dental floss around one inside edge of the groove, then put a new o-ring in the groove so the edge facing the gage or end of barrel was pushed up by the floss. Seemed a little tighter when I pushed the regulator back into the tube but leaked air out the vent hole as soon as I tried charging it. Wanted to shoot it tomorrow on my day off but will have to wait till new seals come.

Missed-Em · « **Reply #458 on:** July 31, 2018, 08:13:33 PM »

Ok, needing help here! Gt my DAR - 22 last evening and played w/ it today, got the barrel clean, scope mounted (that was a struggle) and went to load the magazine

.... Can someone explain in 6th grade English how to load this thing? Directions show a different style mag and I seem to have a mental block on accomplishing such simple task! All help welcome!

BigMike1 · « **Reply #459 on:** July 31, 2018, 08:42:54 PM »

Hi ! You have to rotate the cover and load the first pellet skirt first from the back side .. and then load the remainder from the front !

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Any one ever heard of the Dynamic PCP air rifle?

Author Topic: Any one ever heard of the Dynamic PCP air rifle? (Read 57520 times - 1 votes) )

Author Topic: Any one ever heard of the Dynamic PCP air rifle? (Read 57520 times - 1 votes)
)