If my research hasn't failed me then the UK Arms M24 is a OEM of the Echo 1 M28. So there are some parts that can take vsr-10 upgrade's but not all. If it is indeed the OEM M28 there are a few issues however. The hopup unit is proprietary as well as the piston which in time will most likely become broken. However never fear for "Ranger" is here. "Ranger" and a friend of his are actually in the process of creating metal pistons. I do believe he has a thread about it on this forum. You should check that out.
Well, assuming that it will take vsr buckings you could pick a new one up, Maybe a nine ball one. Pick up a tightbore barrel and that can help out with accuracy and range. But with the hopup chamber being proprietary you can't get a new one like the PDI one.
I actually know nothing about the UK Arms but if it is infact a clone of the M28 then I think I can help,lol.. The pistons will be ready soon I hope. They are able to take a beating.The hopup is like a mini version of the Vsr. The hopup arm fits. I suggest cutting of them terrible fang type nubs on the arm and gluing on a rubber bucking. Them fangs eventually chew into your bucking and you end up having to replace it every so often. I used soft rubber wire casing instead. I shimmed my hopup arm and did the Tdc hopup mod. The barrel spacers the m28 comes with are already good..
I suggest doing the teflon tape mods, cylinder head threads and bucking. As for the lower fps. I would get the laylax pss10 120sp. That gets you about 400fps roughly. Then since you did the teflon tape mods. Reports I read say that wrapping the cylinder head threads gives up to 50 more fps. Lets just average that to 25fps.. right there gets you 425-450 ish.. I would honestly say keep the stock inner barrel because its actually pretty nice. Many people are arguing tightbore is only for short to medium range, not long range.. Personally, I dont care for tightbores either.
Accuracy has to do with the ammo also of course.
I dont know how much knowledge you have on these things so I just over explain just incase..
Am I missing anything guys?
Oh, a good steel piston sear is a nice thing to have when dealing with metal pistons. Ours is aluminum with a stainless steel sear catch. Currently my buddy is having some issues, so I'm not certain how long the hold up is, but I'm certain its worth the wait..
Although I'm not one hundred percent sure what parts will work in your gun. I do think it can take vsr barrels, so look through the pages and see what you'd like. Most people will say that a 6.03 barrel is the sweet spot but a lot of the ones in the link are PDI 6.01 barrels. Next thing should be a new bucking. I've heard good things about nine ball and firefly. Then if you feel the need to get a new spring still you have a lot to pick through. But if the trigger can take vsr-10 sears you'll need new ones. I use PDI sears and there great.
Thats the thing, since I stated back in the caveman days, we all swore by tightbores.. Then recently many people are saying widbores are better and that tightbores are best in shorter ranged weapons. Me personally, I have tried tightbores and I wasnt as happy as I thought I'd be after spending $40-$60,lol.. I tend to stay with stock inner barrels unless they are bad. I cant afford to actually test the barrel options in my m28 right now but I admit, widebore being better doesnt sound right to me, but I've been wrong once or three times before..lol.