Diana 6G Saturday rebuild

Well, thanks to another fine member, here on AGN, a pristine, but ailing, RWS Diana 6G arrived at my doorstep Thursday and coincidentally, so did the seals from John Maccari. Those were ordered as a preemptive strike as the guns are known for the piston deteriorating. 

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This morning I decided to delve into a Giss system. Having never opened up a springer of any kind, I figured it would be a great learning opportunity. 

It turns out it isn't rocket science, one pinion cap had to be helped loose with some Vice Grips and aluminum shim to avoid marring the surface. Same with the end cap, but I held that in the lathe jaws.

I found the replacement rear seal acts as a a perfect spacer to preload the spring enough to remove the sprockets without any tension. I measured the position of the end cap to go back to that position on reassembly, so I keep the gear timing from being lost. 

When I opened it up, I will admit I fumbled the spring and that gave me a chuckle, but nothing took flight. The front seal was not on the piston, it was a chunky mass at the front of the compression chamber, most of it came out with a sharp rap and the rest got knocked out with a copper rod.

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I cleaned everything and pressed the front seal in place and checked for fit. It was tighter than I felt was necessary, so I spun it on the lathe and shaved it down with a vixen file slightly to get the fit better. 

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It went back together without any fuss and all was well, except... I forgot to order a new breech o-ring🙄. I figured it would be a common size and I was wrong.

It sounded like a squeegee when I cocked it, but it fired just fine and started to quiet down after a dozen shots, but that's when I noticed that there was a little puff of air at the breech, so the real test will have to wait until I get a new breech seal and check velocity.

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All back together and looking nice.

I hope that people will not be intimidated with tackling one of these guns if it needs seals. I spent about an hour and a half from start to finish and other than taking advantage of the three jaw chuck to hold the end cap, I used basic tools and a vise with the jaws lined with aluminum can strips to prevent damage to the finish. Sizing the seal didn't require the use of the lathe, it just kept it simple.

I'm looking forward to finding out how it will perform, I just like these older guns, the quality is always a treat.

Mark


 
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the breech o-ring is a 7 x 2.5mm Buna 70 i bought mine from O-rings and more 

the trick to get the gear wheel cap off is take them off when you compress the spring and having the right tools and the 2 pliers are model PH-200 and Wl-270S from IPS

did you have a replace cap filler ??? they come in different thicknesses which can be a problem and my solution was to buy sheets of teflon in .3 and .5 mm and with them i can make any thickness i need 

i did have a chance to use a set of seals from ARH and hated them, they were over sized and once you install them on the front piston which is it's own challenge they are very hard to resize 

you mention gear timing but there really is no timing, the pistol can only go back together one way but you have to put on the right stepped washer with a gap of .3mm so there is no pressure on the gears when uncocked 

having extra parts when rebuilding always helps and sometimes the pin in the cocking linkage and the cleaning if the tube is the hardest part 

i always take the cocking pin center splines down for easier assemble because the model 6 used a plain pin, i hate to have to pound pins out, i need an arbor press

there are tricks to these pistol but they are easier then a FWB 90
 
That's great you were able to do it yourself. I usually do the same but recently sent my 6G off to be repaired as I screw things up way too often as of late. Brain doesn't werq just right all the time, since the head injury, anymore and I do weird stuff that damages things for no reason that I am aware of. Beautiful gun thanks for the post.
 
Diana offered 2 different wood grips as an option but after saying that some years the pistols came with the target grip and over time they have been added and subtracted 

so in catalog 14 they show both the G and M with wood target grips and that would be 1995 and they were 85.00 for right and 95.00 for left yikes catalog 12 shows the same but the grip as a option were 75-85 

back in the day Natchez supplies sold the RWS products but i don't have any catalogs that go back far enough to show the pistols 












 
I've rebuilt a few of those pistols and I think the hardest part is removing the gear covers and the end cap in such a way that they are not marred in the process. I've seen quite a few where people buggered things up with tools that were woefully impractical for the job at hand. And yours, by the way, is a great example with the desirable match style grips.
 
I recently bought a like new in the box Beeman 850 (same as the Diana 6M) with the twist barrel front sight guard and the Giss system. On firing it , not enough compression to push a pellet out. So off to airgunwerks.com it went. 6 weeks wait is what I was told. The Diana Giss system pistols were riding high until FWB pushed them off with their Model 65. Beeman quite selling the 700/800/850/900 series by 1982. I have the Beeman 1981 catalog , so plenty of data was available before I bought my 850. I have some beautiful wood grips for it.
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Today I received a like new Diana6M. The seller said it had not been shot in 10 years and maybe the seals needed replacement. When I opened the box I could not believe my eyes. Not a scratch or mark of any kind. I cocked the pistol (a handful) and placed two drops of Beeman Ultra Lube in the chamber. Ultra Lube is the only oil used for re-coilless rifles and pistols. I shot the pistol over the chronograph with 7.0 RWS WC pellets...493fps...Then with 8.2 RWS WC pellets...433fps.

I shot another 6M this past Sunday at the Diablo Silly Wet Match. That pistol cocked a whole lot easier than this new one. I emailed the seller and asked if he had ever shot the pistol...”20 shots then into the safe.” That explains it..

The 6M definitely likes 8.2grain WC pellets over the 7.0. 

I shot the target while checking the speed. It was shot at 12 yards over a solid rest. The first three shots had the sun in my eyes so I put up an umbrella then shot 10 more...

Not too bad and I am sure it will get better when the pistol gets broken in....



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RidgeRunner,

I was surprised that I got a notification for this thread. I haven't been active on the site for some time and haven't kept up. The funny part is that I wound up getting a Diana 10 and had to do the same thing. It was a time capsule, but the seals had long since expired. Good luck and if you run into any issues, I can try to help.

Mark