mag modification idea from John814ce.....

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John814ce

Re: mag modification idea from John814ce.....

Wed Mar 20, 2019 10:08 pm

That's fine buddy.... but just think about it a .177 loading bolt end is 3mm (well mine isn't now it's 2mm), and a .22 loading bolt end is 4mm. So thats a 1.5mm gap from pellet skirt to loading probe. now if your pellet skirt isn't exactly seated in the barrel (and mine was sticking out about 2mm) when that blast of air comes through the port what's to say its not slightly deforming the skirts inwards somewhat are deforming some pellets causing that odd flyer? (It's not going to make a difference on the fps). Now im not saying it could but at least now I've totally ruled that potential problem out from my rifle. I hope you know what i mean?

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TenMetrePeter
Posts: 1043
Joined: Wed Jun 29, 2016 5:40 pm
Location: Luton Beds UK

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 2:25 pm

I have never seen the point in the brass end. Some of them need an o-ring, some not, some need Loctite. The MPRs and several other AA rifles have plain steel breeches. All I can see in mine is the end of the steel barrel. In your case I might have gone for a new plain-end barrel. They must make them.
Or is it a .22 design requirement eg barrel too thin?
PS did your bolt never have the standard probe or was it just too short?

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John814ce

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 3:53 pm

The bolt was standard, the gun was new. The loading bolt is one piece. Aa sent me an email saying the tech depot say the end of the probe should line up perfectly with the start of the barrel. I responded by saying mine didnt line up and my pellet wasnt seating into the barrel. I think its how aa design it if anyone else can test this then please do.

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tonyc
Posts: 376
Joined: Mon May 29, 2017 10:55 am

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 5:02 pm

I had a look at my S510 (brass insert) but there's no easy way to see if the pellet is seated or to measure where the barrel starts unless I take the barrel out, which I'm not inclined to do when everything is working fine. I might be able to see with a micro-endoscope... if I can find where I put it!

Just a thought: you will have reduced the air efficiency by increasing the effective volume of the transfer port, i.e. the total volume between firing valve and pellet. So, in theory, you should get fewer shots. Also you might find the power curve has shifted, needing slightly higher pressure to be on the equivalent part of the original curve. The difference may not be huge. I don't know what the original transfer port volume is but, if someone can tell you, it would not be difficult to work out the percentage increase and the effect on firing pressure.

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Roger5
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Joined: Sat Jul 25, 2015 8:04 am
Location: Hampton middlesex

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 5:57 pm

Just take the bolt housing off, no need to remove the barrel, and look up the hole, you can watch the bolt push the pellet in, don't forget there's a pellet in there when you refit it though. Rog

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John814ce

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 5:59 pm

No mate the complete opposite, i haven't put more volume in the transfer port are the brass end piece. I in fact have made it more effective because my loading bolt is 2mm in diameter through the brass breech and aa standard size for .177 loading bolt is 3mm. Like i said if you give me a email privately i will send you a pic and if you want you can upload it on here, i dont have a lap top and im not sure if we can upload from smart phone.

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John814ce

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 6:05 pm

Rog he will need to take the barrel off to see the back of the pellet sticking out of the start of the barrel. You can see the pellet pass past the transfer port hole but by not taking the barrel off he wont properly be able to see. It's easy to whip the barrel off mate only 3 screws, i will guarantee you the pellet wont be fully in the barrel honestly mate its how its designed.

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tonyc
Posts: 376
Joined: Mon May 29, 2017 10:55 am

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 7:30 pm

As I said, mine's working so I'll leave it.
If you've made the probe smaller diameter and pushed the pellet in further you have created additional air space... which will reduce initial pressure. There is a gain; it will improve air flow at a given pressure... but the net effect???.

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TenMetrePeter
Posts: 1043
Joined: Wed Jun 29, 2016 5:40 pm
Location: Luton Beds UK

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 7:41 pm

Right, the following statement assumes the transfer port is drilled right through the brass AND the steel barrel. If I am wrong, ignore it!

So if a pellet fires OK the skirt must be forward of the port and therefore fully in the barrel??

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John814ce

Re: mag modification idea from John814ce.....

Thu Mar 21, 2019 7:54 pm

Yes the pellet went in front of the port but not fully into the barrel. The barrel doesnt have a transfer port hole in it or any holes drilled in it. The barrel sits in the front section of the brass breech piece and the transfer port is at the rear of the brass breech piece. My pellets head went into the barrel but not the skirt. Now i believe this is a design floor and if anyone else can try this you will see. Its a piece of piss to check by loading a pellet in the gun then whip the barrel off and look down the brass breech and you will see the pellet hasn't seated..... if im wrong i will give you my gun and scope for free totalling £2500. My pellet now sits flush every time now exactly the same as when you load a tx200 are a pro sport.... and thats how it should be that is perfect.

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