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Thread: Diana N-Tec vs Theoben gas ram.

  1. #1
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    Diana N-Tec vs Theoben gas ram.

    Can anybody speak with authority about the new Diana gas ram guns?

    I have had two Theobens over the years, and I came to the following conclusions: they were good in 22, and not so good in 177. Both guns leaked and needed pumping up every few months. I decided to call it a day with them. Pity because my Siricco 2000 in 22 was a lovely lightweight gun that was a pleasure to use. My Fenman in 177 was deeply disappointing.

    Now that Diana have got into the game, I wondered if their guns also have a tendency to lose pressure and need pumping up.

    I had the pleasure of reacquainting myself with the Theoben brand today at the range, in the form of a walnut stocked Evolution in 22. It was relatively light in weight, and very nicely made and a smooth shooter, and I began to consider trying a gasram gun again.

    The Theobens had very nice stocks. I am not particularly keen on the Diana stocks. The Dianas like most German guns are heavy (not in the league of the HW90 though) compared to Evolutions.

    However the Diana are quite competitively priced and have a good trigger, and if they are more reliable at holding pressure than the Theobens I had, I might consider taking a risk on one.

    What do you reckon?
    Arthur

    I wish I was in the land of cotton.

  2. #2
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    Isn't the n-tec one a sealed unit?

    Sealed unit according to here http://www.airgunbbs.com/showthread....om-Diana/page2

    hatsan does a gas ram that can be pumped up.

    https://sharg.pl/product-pol-103612-...TYPE-1-ST.html
    Not sure if there is a rifle fitted with them or if they are after market ones9
    Last edited by bighit; 20-08-2017 at 10:41 PM.

  3. #3
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    I bought an AR8 Blaser .22 back in April. This is built on the 350 N-TEC. So I can't give a long term report on last-ability.
    I like rammers, and I like this one a lot. But to be fair, this one probably wouldn't be every ones cup of tea. It's the Professional Pro version with barrel weight. Scoped up with Hawke Panorama 50mm AO IR sitting in a Diana Bullseye ZR it weighs in 10.5lbs (the 340 will be lighter). The weight isn't a problem as my favourite rifle is my Diana 48 Black Pro which weighs the same.
    Haven't recorded a new string over the Alpha other than checking to see what increase in power I am getting as the thing beds in. The first couple of ten shot strings were tested after a 100 pellets-
    Using JSB Exacts 5.52's. In FPS, these were the figures for a ten shot string.
    564, 563, 564, 562, 564, 563, 561 564, 564, 562.
    563, 563, 563, 564, 563, 563, 562, 563, 564, 563.
    It now runs at 11.5fpe.
    Not particularly pellet fussy.
    The rams are made by Bilstein in Germany. They can't be re-pressurised if they lose pressure.

  4. #4
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    I had a 340 lux with open sights, apart from the odd bit of plastic I really liked it, but it produced around 15 ft/lbs.

    Was a very nice gun, highly accurate and nice trigger and no horrible noises from the ram when being cocked.

    It went back to the dealer (who is also gun smith) but he could do nothing with it due to the ram being a sealed unit.


    I couldn't understand how they had got the power so far out - surely filling the ram to a pre determined psi would mean it corresponded to ft/lb


    Waited weeks for a replacement, nothing ever landed so kindly got a refund (without any quibbles).


    PS Bluing wasn't up to HW or AA standards but still ok but the stock compensated for that, if ordered again I'd seriously consider the optional non scratch finish.
    Last edited by capt hindsight; 21-08-2017 at 12:26 AM.

  5. #5
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    Thanks for the replies.

    I wonder why Theoben didn't use a sealed unit.
    Arthur

    I wish I was in the land of cotton.

  6. #6
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    Quote Originally Posted by capt hindsight View Post
    I had a 340 lux with open sights, apart from the odd bit of plastic I really liked it, but it produced around 15 ft/lbs.

    Was a very nice gun, highly accurate and nice trigger and no horrible noises from the ram when being cocked.

    It went back to the dealer (who is also gun smith) but he could do nothing with it due to the ram being a sealed unit.


    I couldn't understand how they had got the power so far out - surely filling the ram to a pre determined psi would mean it corresponded to ft/lb


    Waited weeks for a replacement, nothing ever landed so kindly got a refund (without any quibbles).


    PS Bluing wasn't up to HW or AA standards but still ok but the stock compensated for that, if ordered again I'd seriously consider the optional non scratch finish.
    was 20 or so years ago I fitted it but I'm sure when I fitted a AWT/THEOBEN one to my air arms Hi-power I had to cut the spring guide down to a certain length. It was part of the end block. If the power was too high I'm sure it's said to trim what was left of the guide down a little and continue to do until it was under 12ftlbs . I know that's what I did. I'm sure I filed it to get it right. I had my own chronograph that looks like the pro chrono . Took a few strip and builds . I got it to 11ftlbs and used a washer in the piston to bring it up to 11.5ftlbs.



    Instruction sheet here for an AWT/theoben aftermarket ram. I cut my spring guide longer than the 4mm to start with as I heard it may be too short and lower on power.
    http://www.network54.com/Forum/79537...rew+things+up+...
    Last edited by bighit; 21-08-2017 at 02:24 AM.

  7. #7
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    Quote Originally Posted by Arthur John Smithsplease View Post
    Thanks for the replies.

    I wonder why Theoben didn't use a sealed unit.
    They sold aftermarket ones made by AWT.

    as I said in my post above , getting it to the power could be a hit or miss.

    So a adjustable one via a valve may be easier to fine tune.

    If you fitted a AWT one to a rifle and it was too high power wise it's possibly going to take a fair time to fine tune. And as I suspect , the rod in the ram being hardened may have been seen as too much of a time consuming job for mass production.

    If say it took 3 hours or so for the home tuner to fit one , it may have taken the makers the same time but time is money to them .

  8. #8
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    look no hands is offline Even better looking than a HW35
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    I've had two AWT drop in rams and both have lost pressure over time but unfortunately you can't pump them back, I currently have a Theoben Sirocco 2000 in .177 and it's lovely to shoot, when I received it at the beginning of the year it was doing 10.5ftp which is the ideal power for .177 and makes them shoot sweet, I've hardly touched the rifle all year as I've not been out hunting due to work commitments and have only had a few shots in the back garden when fitted a different scope a few months ago, so I couldn't tell you what power it's doing now or if it's held pressure over the summer, if I remember I'll chrono it soon and find out if it still has air in it, I think with Theobens, you either get a good one or a bad one, this is my third rammer and the last two never lost pressure.

    I was always told many years ago by a well known gunsmith not to use drop in rams as they fluctuated in power because of different temperatures effecting the gases in the ram, so I've always left springers as they are and just used the proper rifles if I wanted a rammer.

    Pete
    Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in

  9. #9
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    If the Diana gas piston rifles are designed for our power limit then they may be worth investigating. I'm told the new Diana triggers are very good. Theoben triggers always appeared to suffer too much creep and felt heavy from when I ever shot a Sirocco in the past. I've looked at the N-tec Diana's and do like the look of them and would like to have a shot or two with one of their models before committing to buy one.

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