Dboys K98 conversion. Another picture guide

[kalashnikov_kid]

I'm starting to build a K98 springer using a Dboys 98 and a ACM vsr. Now the object of this is to produce a low cost effective rifle I can use for skirmishing and general showing off :giggle:

Lets begin

The Guns

The K98. Bought second hand for £55 at my local site. It's full wood and as per usual internally terrible!



This will be fully stripped (obviously) and the stock re stained and oiled. the metal work will get the same treatment as my MP40 build.

The donor gun. An ACM VSR "clone" most likely a well MB03 if google is anything to go by. Bought from HK Chrono'd at a healthy 465fps!




and side by side




Stripping and tuning the Internals

First things first separate the stock and action. This is the bit you need.



Now this is where this build got interesting... This supposed VSR clone was a little different. The mag catch was part of the hop block and NOT part of the stock. Perfect for my conversion as I've heard that cutting the VSR catch is a bugger :happyclap:



This however was the the only positive variation on the VSR platform. It gets worse.... The cylinder had been sanded to taper it. I assume it was a fit issue.



Opening the cylinder reveled a Type 96/VSR hybrid piston, plastic spring guide and a tapered (and slightly rough cut) cylinder head.





First things first, get some meths and clean the whole assembly down, Th grease looks to be good quality silicone grease but I always do this as part of a build. Then take a small o ring and fit it in the grove on the front of the piston cup push it down so it spreads out the cup lips slightly. Super glue in place.



Next I like to bore out the nozzle a little. Clamp the head in a vice and find a drill bit that just fits in the nozzle then take the next size one up and carefully drill thru the hole. I don't like to go more than 5mm i this case I bored it out 3.5mm to 4.5mm. If you want now is a good time to polish the taper on the cylinder head. Then wrap PTFE (teflon) tape around the cylinder head threads. Make sure you wrap anti clock wise to stop it from un winding when screwing in. Lightly grease the piston cup and internal walls of the cylinder. I use Molycoat silicone grease. Sorry chaps but no photo for this stage. I'll look into getting one tomorrow for the sake of the guide.

Next stage will be the Hop Unit and the horror story it contains... That'll have wait for now as I'm off to bed. Watch this space

Thanks

Dave

[kalashnikov_kid]

Re: Dboys K98 conversion. Another picture guide

Morning everyone. Sorry for the wait but Christmas and Lewis guns have eaten all my spare time

The Hop Unit

This is the Hop unit.



It is a vsr style hop unit. I've not got a VSR hop to hand so can't do a side by side sorry.

And the top showing the adjuster



All looks good until you open it. This is the bit that ruined my day...

2 PIECE BARREL!



Not only a 2 piece barrel BUT a non standard hop, solid bar type adjuster AND non standard barrel lugs in the hop unit! By standard I mean VSR or AEG type. Oh goody :roll:



I'd LOVE to find the guy responsible for inventing the 2 piece barrel and punch him in the trousers. It's just silly. Stop it

This ALL has to be changed if I'm gonna be happy with the final result. Best I could come up with (without changing the Hop for a VSR) was a combo of modified VSR Rubber and AK length (~455mm) AEG barrel. I'll show you how, first up is the hop rubber...

Take a VSR type rubber and trim off the ridge on the barrel end. Before (left) and after (right)



Next, remove the rib one the side of the rubber. Sharp side cutters work well Before (right) and after (left)



Now your gonna need to trim down the barrel locking lugs in the hop unit. They act the same way as a c clip does in a normal AEG. The original barrel had a radial cut out. AEG barrels have two cut outs at the 3 and 9 o'clock position.

THE MOST IMPORTANT PART OF THIS NEXT STAGE IS MAKING SURE YOU HOP UNIT AND NEW BARREL ARE PERFECTLY ALIGNED!

Take a dremel with grinding disk (or hand file if you don't have a dremel) and firstly grind the lug down so it's the same width as the new barrel grooves. The You'll need to flatten back the bit of metal you have left so it's flat. NOT remove it but make it straight and level. This will take some time and testing to get it to fit with the barrel. Don't cut too much in one go and test fit regularly. Make sure the groove at the bottom of the barrel lines up with the join line on the unit, this is a good indicator your doing it right

Before (right) and after (left)



Once both sides are done and your happy with the fit. Put the hop rubber on your barrel and test assemble the hop unit.

My modified unit



Wrap a few layers of PTFE tape around the rubber for an improved seal. Make sure you do the whole length of rubber, Reason being the clone nozzle is narrower than the VSR one and the rubber needs compressing slightly to improve seal

At this point I suggest a quick re build and test fire. When you rebuild the hop you'll notice the hop arm doesn't quite line up with the hop window on the new barrel. Don't worry that part comes in the next update If you used an AK length barrel you'll notice it sticks out the end by an inch or so. Don't worry about it. It'll all go in the K98 just fine

A good way to test compression is put you finger over the end of the barrel and cock the EMPTY rifle and fire. A good seal will slow or even stop the piston towards the end of it's travel. Alternatively use a chronograph and look for FPS increase and shot to shot variation.

My rifle went from 465fps out of the box to 445fps with 7fps variation after 200 rounds in stock configuration. To 498fps with 2fps variation after the build. Not too shabby

Next part will be up soon. I'll tackle the hop arm and trigger unit. I'd like to say at this point if your not a confident modder and IF you can get a BAR 10 instead do it. If I had to pay for the extra parts I'm fitting this way would have been more expensive. Plus it'd be nice to be 100% vsr compatible.

Saying that if the accuracy is comparable with a VSR and the power stays where it is I'd be a lot cheaper than a upgraded VSR. Only time will tell.....

Cheers

Dave

[Cerbo Knight]

Re: Dboys K98 conversion. Another picture guide

This is the point where I really regret selling my Kar98 because of the impractical shell ejection!
Really nice guide Dave, I look forwards to seeing it done, and seeing if I can pick up a cheap kar98 somewhere :D

[Ominous Slayer]

Re: Dboys K98 conversion. Another picture guide

Looking forward to the end result!

[Siggi]

Re: Dboys K98 conversion. Another picture guide

Well, that de-escalated quickly. Lol.