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Gas strut, how to compress the spring?

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7 replies to this topic

#1 Guest_gunut_*

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Posted 25 January 2006 - 12:16 PM


I would like to fit a theoben gas strut in my BSA Lightning, I bought the strut in UK nearly 3 years ago and finally decided to fit it. I am now gathering all info I can find because my first attempt failed miserably due to the pressure required on the spring to take the retaining cross pin out. I got into a cold sweat trying to push the spring in with common tools and gave up as I did not want to damage the BSA. I did not want to use a vice either ( as advised in the BSA instructions to remove the spring) as it would mark the blueing. I got the Theoben instructions to use a '' spring compressor'' I don't know of such a tool! and therefore searched the net for clues.
I found 2 interesting comments:
...gas rams are easy to fit. You will have a problem compressing the ram, but you can use a car scissor jack to achieve this in any standard width doorway. I have made the templet as recommended by theobens, but have also used a piece of 1" copper tube with a slot cut in it.
The ram fits and works well I have not refitted the old spring again.
You can contact me for advise if needed.

....as an engineer I made my own device and I can take the old spring out and put the strut in, in under six minutes. If anybody requires the plans or would like one made for them contact me on the email at the bottom, cheers, Russell.

if you guys have done this or have info or step by step instructions how to replace the spring without damaging the rifle I would really appreciate your comments. Using a car scissor jack in a doorway sounds reasonably feasible but I am afraid that the barrel axle may get damaged or that the barrel snaps open under the pressure or bend, should I use a Vice as well? Is this the only way to DIY? No gunsmith here and no local expertise! I sent a mail to the guys who wrote these comments, but these comments are from 2003 and 2004, maybe the addresses have changed. thanks for the help. another question, will accuracy suffer from this swap? I saw mixed comments about the subject concerning other rifles, some say yes, some no...and lastly, can the cross PIN go out either way? ( from left to right and inverse)

thanks & Regards

#2 Artfull-Bodger

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Posted 25 January 2006 - 03:04 PM

I used a carpenter sash cramp I bought on ebay for a fiver!!

fitted an anti slip block to each end and hey presto job done!!

#3 fenman

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Posted 25 January 2006 - 07:14 PM

If you offer a free holiday in MAURITIUS i'll come and fit it for you cool.gif

#4 fenman

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Posted 25 January 2006 - 07:25 PM


Have a look at Rifles & Pistols Mon 1 sep 2003,

This may be what you are looking for.

#5 Guest_gunut_*

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Posted 26 January 2006 - 05:55 AM

thanks for the ideas and replies, the post dated 1 sept. 2003 is exactly what I was looking for, with pics and all, couldn't be any better!
Fenman, thanks for the offer, if I get stuck I'll think about it!


#6 Guest_shippyt_*

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Posted 13 August 2006 - 06:56 PM

Just got my spring out of my supersport by tapping a flat headed screw driver between the retaining pin and the mainspring guide (the tube running through the middle of the spring). This compressed the spring and allowed me to push the pin out but I'd only recommend it if your changing the spring as it-rubbish- the mainspring guide.

Just hope fitting the RAM is nice and easy....... rolleyes.gif

#7 Guest_Slug Dundee_*

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Posted 16 September 2006 - 04:55 PM

Look in your Screwfix catalogue. They've got at least two sash cramps that will do the job at around £6

#8 bulsaye

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Posted 17 September 2006 - 01:49 AM

Yes- the cross pin can be slid in from either side... just make sure you've compressed the guide and spring about 8mm before attempting to push the pin out. The pin is not a smooth, solid cylinder! RB

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