DMR's

[LukeCDC]

Re: DMR's

I gor bored and put a scope on top of my p90, thats all i've since sold it on.

Anyway so far a DMR is classified as a rifle with:-
1. Fps over 350.
2. Played with a 30m med
3. Semi-auto only

After that it sounds like the general rules are :-
1. Heavy weight BB's
2. Long barrel
3. "upgraded hop"
4. Electric

Everything else seems to be personal preferance, or site rules, am i close to the mark?

Sent from my GT-S5830i using Tapatalk 2

[Caldymoose]

Re: DMR's

I gor bored and put a scope on top of my p90, thats all i've since sold it on.

Anyway so far a DMR is classified as a rifle with:-
1. Fps over 350.
2. Played with a 30m med
3. Semi-auto only

Not so much 'classified' but 'generally'

After that it sounds like the general rules are :-
1. Heavy weight BB's
2. Long barrel
3. "upgraded hop"
4. Electric

Everything else seems to be personal preferance, or site rules, am i close to the mark?

Sent from my GT-S5830i using Tapatalk 2

1. Heavy Weight BB's - not always. I run 0.25-0.3's in my PTW, ran 0.36's in a KWA LM4 gas rifle and run 0.3s in a pistol every time its used. Sure, a heavier weight round will have a great positive effect, but its by no means a 'rule'

2. Long barrel. Again, this is a common misconception it seems in airsoft. Sure, in the real world, a longer barrel DOES help due to ballistics, in airsoft it doesn't, and theres some evidence to suggest a shorter, wider barrel is actually more beneficial to us airsofters. But thats a whole different topic... So again, this shouldn't define a DMR. And even then, what constitutes a 'Long barrel?' 10"? 14.5"? 16"? 20"

3. Upgraded Hop. Again, very difficult to define as this is the one major part that will have a positive effect on the BB, and that goes for any rifle, regardless of if its a short MP7 or an M16. Its also such a common item to change/modify/upgrade that it happens to most rifles. So again, its hard to use this to define a DMR

4. Electric. Not at all. You can get many gas rifles which people use as DMRs. Not to mention Polar Stars or other HPA systems, as well as the normal Propane/Green Gas/whatever expanding gas takes your fancy and the Electric ones. So again, sorry to be the negative party pooper, but you can't use this to define one either!

I think what your trying to do by 'defining what a DMR is' is going to be very hard, there is no set definition of what one is, but its a set of guidelines or parameters. They will usually fall into Category X, Y and Z, but the site may wish to add, refine or define additional parameters, or even create their own. It all depends on the site that the rule will be used at, what the players might want and what the site managers/marshalls think will run the best.

[Viper Scout]

Re: DMR's

Caldymoose.....you da man!
Concealment is also part of the 'package'.
There is no greater pleasure than finding an excellent hiding place and watching the enemy walk passed you just feet away.
Especially if you have a 'last man standing' game.

[GiantKiwi]

Re: DMR's

GBB SR25 is definitely on its way

I'll add my tuppence to this, as I have built many, many variations on the concept. As has been stated semi locking is a must but there are certain foibles attached with that which I will go into.

First a disclaimer, i will mention higher fps a lot in this, but the higher fps does not equal more range, I know this, you should know this, we all know this etc. It is ONLY to allow the use of much heavier ammo without drastic hits in performance.

AEG's

Only rifles based on 2 gearbox versions lend themselves to the aftermarket DMR concept well, V2 & V7, both because of the process of the semi lock. Electronic locks are not acceptable by any means as they usually only require a few seconds work to disengage. Mechanical locks are where you have to go, mainly for adherence to site rules. V7 is just a case of disengaging the cutoff lever, and V2 requires modification of the selector plate. Both not exactly rocket science.

However.

V2 gearbox shells do not lend themselves well to the extra stresses involved with the need for a higher rated spring to reach the higher fps. Heftier springs, means more torque is needed to pull, which requires a high torque motor and gear set. More stress on an already flawed design? Good luck to you, its not a case of if it will crack the shell, more of when. You can radius corners, and various other tweaks, but its just prolonging the inevitable.

V7's on the other hand, are almost too good. No major right angles, much stronger shell and as stock come with a much torque-er gear ratio, but it will still likely need replacing regardless.

GBBR's

I don't quite get the fascination with AEG's being used for DMR's when the gas platform allows the principle to be achieved much more easily; at a much, much lower final cost. Semi lock? Easy, modify the selector OR sear and remove the capability to engage auto. Done. FPS? Stronger gas, NPAS valves etc, Done.

UPGRADES
With AEG's its a little more involved, but the main principal parts to concern yourself with are Hop and Barrel.

Hop is the ONLY thing which should be dictating the flight path of the bb, so if anything else has you've instantly failed.

Barrel - Widebore is king here, any dispute in that fact is only heralded by those talking out of their backsides, PDI did the research, it is actual FACT not conjecture/myth/legend. As wide as you can get, Orga Magnus 6.23's are my personal preference, and P* users love them as well for obvious reasons. Widebore means that the bb's are flying on the air volume (cushion of air concept) and only corrected by the hop. Length is another factor here, it cannot be any shorter than 180mm and no longer than 433mm, with a sweet spot being around 370mm (+/- 2%).

Now on to the more crucial bit, DMR's rely on air volume, and lots of it. With AEG's that is finite and wholly down to the volume of the cylinder which often is not very much. SO bore up kits are there to fix that, which generally only work with certain gearbox configurations (take a guess...). GBBR's....have effectively endless quantities on this front for our purposes. Watch a video of a GBBR firing, see how much gas is sent out of the muzzle? Most of that is wasted.

Other things to take into account, because air volume is precious, any leaks make a big impact, so air seal needs to be nigh on perfect. Expect to spend many hours perfecting your PTFE tape skills. ANY vibrations in the barrel have a chance to cause bb deflection, and thus bye bye range and consistency at range. Solution? Spacers to fill the gap between the inner and outer barrels. VSR owners will tell you of this majorly tedious plight, but once done well it can improve results noticeably (I suggest you invest in some calipers for this bit).

BB's

Trial as many different brands as you can, because unfortunately this can make or break the rifles effectiveness. You will need at least 0.28's, but no higher than 0.36's (for the last one I built, I bought small quantities of 15 brands in all sizes between those to decide on the final one).

There is more but as I started writing this at 5am and it is now gone past 6, i've had enough for now.

[Blackheart]

Re: DMR's

Seriously considering the new TM 417d to make into a DMR.

[Heinz]

Re: DMR's

I'm afraid i'm going to have to disagree with a few of your points GiantKiwi.

1: PDI found that 6.05 was the best diameter for a barrel when you're talking about accuracy at range. The Orga's work great (I had one of the first ones in the UK, back when you had to email Sebastien to get a shipping quote to buy them direct!), but they aren't the "miracle barrels" that some people claim they are (HUGE amounts of research have been done in the PTW world on this. The performance improvement is marginal over other premium products). I didn't find much of an improvement when I had a 6.23 Orga in my P* either over the custom-cut PDI I had run previously - both were damn good.
2: Circa 450mm for barrel length. ASM may be full of assholes (myself included), but there's a lot of exhaustive testing carried out on there, and 450mm came up as the magic number. To paraphrase Monty Python "Then shalt thou count to 450, no more, no less. 450 shall be the number thou shalt count, and the number of the counting shall be 450. 300 shalt thou not count, neither count thou 370, excepting that thou then proceed to 450. 650 is right out"
3: Bore up kits are totally unnecessary at the DMR limits used in the UK. Your cylinder volume is more than sufficient unless you're running a truly stupidly long barrel - and why would you want a 650mm barrel if you don't have to? It reduces accuracy.