[Sticky] K98 Springer Projects

270 fps,must be an air volume issue as the sp130 pdi spring did nothing to raise it so more tinkering,i can get another 4mm stroke, doesn't sound much it might help.

cracked it ,made up a new piston that's 4mm shorter,cut 2mm of the end nub of the plunger style air seal and presto 6mm more piston travel and 295-305fps on the standard spring.im too tired to mess about more tonight but tomorrow i may take another inch of the barrel and fit the new spring,but it may need shortening to fit in there now as it was completely compressed with the standard piston travel and i reckon the spring would ground out before the trigger sear engaged.i cant believe i got 30fps from another 6mm travel though,well chuffed its now a workable rifle

new spring fitted without clipping ,now 320 fps and all done ,well pleased

So far your's is the only success story. Congratulations! Would you mind posting pics of the new cylinder+nozzle and the new piston? How did you go about sealing the leaks between the cylinder and the nozzle? Oh and did you have to remove the extractor? How does it should with the vsr10 hop and barrel? Is it much tougher to push the bolt back in with the stronger spring?

i'll post pictures of the parts later but the seal on the nozzle is still an "o" ring just raised a little ,the little part of the extractor system that pushes the old shell out has been replaced with a hook so the shell is held in place both sides ,the spring is not at all heavy in comparison as its only giving a 20 fps increase,in fact a standard dboys springer would be lifted by that spring and its a straight swap also cutting the 2mm of the nub of the piston seal gives an extra 10 fps on its own without having to make up a special piston .accuracy is what you would expect from any vsr running 320fps and could be increased with better hop rubber and tight bore barrel.

first the pistons side by side there is only 4mm difference,mine is the bottom one.

next the nub on the front of the piston seal needs removing,before then after


then an "o" ring is superglue'd into the seal to spread it out for a better seal,i couldn't find an exact size one so cut one down and stuck it back together,looks like a ton of glue but its mostly silicone,you must be careful and use as little glue as you can.

next shows the pistons installed,mine is at the top and a stock one below,notice how the piston is further forward in the bolt and i've elongated the ramp for the sear helping engagement also note the spring with greater number of coils.

two shots of the bolts cocked showing the port in the side of the bolt where you can see on mine in the first shot that a greater amount of the piston seal is visible and demonstrates the extra piston travel compared to the stock piston.


finally a couple of shots of the shell/nozzle i made compared to a dboys shell and bolt combo and a vsr bolt and nozzle,i hedged my bets and made the combined bolt and nozzle the same length as a vsr bolt so if i had to give up then the magwell would be in the right place,im now thinking about the possibility of turning the mag through 180 degrees so that the release catch is at the back,then the nozzle would not need be so long.


lastly and i have no picture,there is a drift pin that is pressed into the front of the bolt for no reason that i can think of as it is goes right through the front top to bottom and partially block's the air flow out of the bolt ? i cut it in two shorter parts and pressed them in ,one from the top and one from the bottom so the air passage is unblocked.
its all little gains but they add up in the end.

Nice one mate! Great news

Thanks for the pics! Great bit of airsoft engineering! BTW, how is the shell/nozzle connected and sealed against the bolt/cyclinder?

the bolt has a small piece on the front on the left that when you pull the bolt back helps to eject the shell on the standard bolt,i replaced it with a piece that hooks onto the base of the shell instead so the shell is not ejected,there's another sprung hook on the right of the front of the bolt that pulls the shell back out of the chamber and that secures the other side.im afraid i couldn't get a good photo and the drift pin is locktighted in ,after this weekends over i can remove it and take a photo.

a last word on my k98 dboys hybrid after Eagles over the Rhine ,a pretty good day with only one niggle that caused the bolt to stop sliding forward a few times,caused by the plastic bar on the side of the bolt moving forward in its mounting and jamming the bolt,think i have it solved and as per usual from dboys it was just a slioppy fit.
Now onto new business, this is another dboys vsr conversion in the more traditional manor for our own Cheeky Chappy.
so far i've cut back the rear of the breach on the vsr to fit into the tongue slot in the stock,opened out the stock to take the trigger assembly,slimmed down the trigger assembly,milled out the trigger guard to fit the trigger assembly and cut the tongue off the back of the dboys breach and milled to fit over he back of the vsr breech.

Nice one Dadio.

Looking good Gav. I can't wait. My excitometre is climbing rapidly.

Steve.

little more done today,outer barrel cut down and fitted,next is cut the mag well and make it all work then on to the cosmetics ,adding the sights ,fitting the bolt handle ,bolt catch etc...
the outer barrel was cut to length then turned down to 14mm then a steel sleeve made inner die 14mm an outer 26.5mm to have the outer barrel fit into it and the sleeve slide into the cut down vsr outer barrel ,two screws run from the outer vsr barrel into the spacer and through into the dboys outer barrel,then the spacer is cut and shaped to fit under the top wood hand guard without cutting away the wood,some wood will need be removed over the hop unit but a minimal amount .i plan to keep the barrel band attached to the rear sight when i cut the sight off the dboys outer barrel in order to hold down the top hand guard,this will also ensure the sight is in the original position.

do any budding chemists in our midst know how to remove the nickel plating from the dboys bolt without removing the copper plating under it? i have a wonderful chemical "liver of sulphur "that leaves a lovely finish on copper,leaves a nice blueish silver finish but after a little experimenting trying to sand the nickel off i found that all to often i went through to the alloy underneath that doesn't take the finish .so is there a chemical that will strip the nickel but leave the copper?

Dadio, Have sent you a PM.

last update on my-own dboys/vsr hybrid ,just replaced the hop rubber for a pdi one and fitted a mad bull black python barrel ,huge improvement in consistency and accuracy over the china clone original parts,wish i'd had the time before eagles ,i may have had a few more kills

experimenting with an acid that was recommended to remove the nickel coating and after 3 hours it looks more like the pot metal is dissolving,not to worry as its just a scrap bi that wont be needed in the build ,im going to leave it over night as whatever is happening is quite slow but im anticipating failure.next will be electrolysis.
oh almost forgot,i started cutting the mag well ,so far i have cut out the recess for the magazine catch and the hole for the release button and cut the catch from the old stock and slimmed it down as thin as possible so it leaves a little wood under it in the stock,now just need to cut the rest of the hole for the mag but before that i need to secure the breech and barrel into the stock so the mag well will be in exactly the right place.

acid failed it started eating the pot metal leaving the outer coatings totally intact
never mind
anyway mounted the breech and barrel assembly, i found that the screw that holds the outer barrel to the breech lines up perfectly with the front screw hole in the trigger guard so i replaced the screw with a piece of m3 studding (3mm threaded rod) and a nylock nut,then drilled and tapped a hole into the original screw for the trigger guard so that it screwed onto the studding,i had to reduce the size of the screw head because the mag well intrudes on the space a little but it works really well.
finished cutting the mag well ,only problem is how thin the wood is over the release catch so im going to have to strengthen it with resin, i'll cover the inside with resin then cover the resin with cling film then re-assemble the gun,this should give the maximum thickness and strength.

also cut out under the upper hand guard to fit.

really only the cosmetics to go now.it fired it's first shots tonight too and fed perfectly although i had the power re-stricter in so only 225fps,made me worry at first as i hadn't remembered it was in

Excellent stuff mate. I think the resin/cling film idea is very clever.

Steve.

Excellent stuff mate. I think the resin/cling film idea is very clever.

Steve.

Indeed, I normally use teflon tape for a close fit because it is so thin, but cling film sounds so much easier.

well the re-enforcing worked well,i used araldite in the end as the resin was too runny and would have ended up everywhere but its done and a lot less fragile.cut the rear sight off and shaped it underneath by first milling it then using heavy grit silicon carbide paper wrapped around the cut off piece of old barrel i sanded it to a nice fit,it will be glued and screwed into place as well .its just resting in place right now but it gives the idea.