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AK DMR?

Something a bit different: WE M14 (with Ra-Tech trigger group) inside a realsteel TROY S.A.S.S. (Semi Automatic Sniper System) chassis. Very nice high-end chassis, CNC aluminum, the M14 needs a f

Hopefully this isn’t heresy, here’s my latest DMR build.  KJ Works KC02, gutted and refitted with Rogueworx internals. Stuck in a Samson B-TM stock and given a custom turned tapered outer barrel.

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Part of the game. Not my problem if the fields rules are stupid. There are countries that play 500fps full auto, so I don't see much of a problem.

 

You arrogant irresponsible twat, YOU are using a WEAPON. YOU are responsible for THE SAFETY OF OTHERS, as well as yourself. If you BLIND someone are you going to say 'it's part of the game, not my problem' before or AFTER they ram that monstrosity up your rectum and break you in half.

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Dude...it's fun and games until you shoot through some poor sods mesh eyewear or smash his/hers teeth. With that energy lip wont protect too well anymore against .4g (compared to lighter). And as said it's not cool to make 'em bleed either.

 

Time for you to stop and think what your doing..

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Part of the game. Not my problem if the fields rules are stupid. There are countries that play 500fps full auto, so I don't see much of a problem.

 

Ladies and gentlemen, the product of America's current education system. A complete lack of morals and integrity.

 

Please put me out of my misery. Guys like this are why I quit working in Airsoft retail.

 

On the Up side, here is a DMR I built from a PTW platform. Currently working on a Mk12 Mod 1 for myself.

 

IMG_1173.jpg

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Where I live all of the other polarstars go off of the same setup as I do, follow the fields rules. Nobody has gotten hurt, mesh eye wear is stupid and not allowed at any field I've been to. Don't hate me for simply using my gun (in field limits) like everybody else is.

 

Unless your field limits say it's acceptable to use a 4-5J gun in game, you are cheating. Simple as.

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Unless your field limits say it's acceptable to use a 4-5J gun in game, you are cheating. Simple as.

Thing is Short Stack doesn't think he's cheating because his site seems to be run by hairless baboons and recognize power limits as a reading of fps at face value. I doubt they know how to calculate for Joules much less spell it or even know the concept of power creep as much exhibited by gas guns.

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Alright, back to topic please. We won't be able to convince him and he'll learn the hard way. If you don't respect the game, the game will beat you. Always has been that way, always will be.

 

Question, and it should go in the SEAL thread but you all may know: any info on what the modern DEVGRU Recce rifle is looking like? M4-based platform, or 416? Someone post some...

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Ladies and gentlemen, the product of America's current education system. A complete lack of morals and integrity.

 

Please put me out of my misery. Guys like this are why I quit working in Airsoft retail.

 

On the Up side, here is a DMR I built from a PTW platform. Currently working on a Mk12 Mod 1 for myself.

 

 

Parts list? I have a P* equivalent of your Mod 0 (posted in its AEG form before I swapped the stock out).

 

Cheers,

Piano

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Question, and it should go in the SEAL thread but you all may know: any info on what the modern DEVGRU Recce rifle is looking like? M4-based platform, or 416? Someone post some...

 

A Nigh Force Optics employee posted the only known photo of a real Recce in ar15com:

 

utf-8BSU1BRzAwMjMuanBn-1.jpg

 

http://www.ar15.com/forums/t_3_118/303894_Pic_Request__Recce_style_rifles.html&page=53#i5314075

http://www.ar15.com/forums/t_3_118/520524_Official_Mk12_Mod0___Mod1_Photo_and_Discussion_Thread__Part_II.html&page=80#i5342324

 

"I posted a picture a few weeks back of an actual Recce rifle in the Recce rifle thread it's not nearly as fancy as all the "clones" pictured in that thread. The Recce rifle is a Dam Neck thing as the regular SEALs used the Mk12 quite heavily. I work with the guy at the unit that built the Recce rifles and while some of the older guys still use them, the current "Recce" rifle is a 14.5" HK416 with Nightforce 2.5-10x24's in extra high UniMounts.

 

It's essentially a Mk12 Mod1 with a different barrel. It uses a 16" Lilja barrel with carbine length gas system and still uses the rifle length FF RAS. Here's one with a 2.5-10x32. "

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I actually got to use my DMR in action at a game recently.While the performance was great the gun wouldn't fire more than a couple of shots. Having put hundreds of BBs down it since recieving it back from the shop i was rather puzzled. I was using a 7.4 15c 2200mah Lipo. When i got home & looked into the problem i realised this problem hadn't occured before because i was using a 7.4 25c 2600mah battery. I have a suspicion that 400mah shouldn't make a differance,so does anyone have any ideas?

Here's me at the game before it started.

545582_10151039249276020_1712212632_n.jpg

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I'm guessing the setup has a higher peak drain which the 15C is struggling with, whilst the 25C can handle a higher peak current draw which is sufficient to get it ticking over nicely.

Have you used the 15C since it came back from the shops and had it working fine and this is the first problem? Or is it the first time you've whacked the 15C in there since it came back to you?

It's possible if the 15C was working OK and has just started being a pain that it didn't go through a complete charge cycle for whatever reason - try charging/ balancing it again.

 

Personally I'm betting on the gearbox needing more power than the 15C can comfortably discharge since whatever happened to it in the shop. - If this is the case, it could be a few things:

- the AOE of the motor is too tight, putting extra strain on the turnover,

- the gears are shimmed too tightly and need more power to turn over,

- if there is a stronger spring in there that will need more power to be cycled (I don't have any LiPos with less than a 25C rating so can't say what effects this may have - I can pull M120s comfortably with a high speed motor and a 25C 7.4. - The spring change will most likely be in combination with one of the other factors than the cause alone),

- if it's a new motor it may be a higher torque rating than your last one and need more power to turn over (I've seen this before - I have a high torque which needs ~35C 7.4 to turn over comfortably (won't perform at all well with a 25C 7.4) or 15C+ 11.1, whilst a high speed motor in the same setup turns over nicely on a 7.4 25C)

**- Dependent on how old the motor is, it may have worn/ coils may be degrading requiring more power to turn over the same **

 

If I had to guess, I would say that options 1,2 and 4 are the most likely causes, but realistically it could be several of them together (or something else entirely that I haven't thought of). If you could elaborate on what it had done/ what is different between when it went in and presumably worked fine on the 15C and now when it doesn't it may help narrow down the cause.

 

**Another idea I had

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I actually got to use my DMR in action at a game recently.While the performance was great the gun wouldn't fire more than a couple of shots. Having put hundreds of BBs down it since recieving it back from the shop i was rather puzzled. I was using a 7.4 15c 2200mah Lipo. When i got home & looked into the problem i realised this problem hadn't occured before because i was using a 7.4 25c 2600mah battery. I have a suspicion that 400mah shouldn't make a differance,so does anyone have any ideas?

I had exactly the same problem with an up-graded TM EBB socom , I bought a 15c 2200 lipo to go in a PEQ15 and it just about coped but when I stuck a 'normal' sized 25c on it it ran fine , so that's what I now run it on (in an older style PEQ) .

Hope this helps mate .

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I sent it off for the work of fitting the rail as soon as i got the gun from Hong Kong. I tend to use the biggest MAH battery as a habit. I've considered the motor might be bit tight or the shimming. I'm going to try the motor as a first thing i address. Since i've been busy for the last 3 weeks i haven't really had a chance to try & sort the gun. It will only take me a couple of hours to address the potential problems.

I used the 2200mah battery in my Sentry gun & it worked fine,i don't see any reason other than those suggested why the lower MAH batterys shouldn't power the DMR.

One of the options i am considering in the near future is replacing the metal bushings with the appropriate bearings. The gun is fitted with an ASCU & locked to semi auto only.The selector lever can't pass the post on the reciever in front of the semi auto mark. The gun is shooting at just under the 450fps mark on .2s but the FPS lowersto about the 340 mark using .3s.

When the gun was working i could put a BB through a narrow slot to shoot the person hiding there{much to that persons surprise}

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As the gun is new I'm guessing then that it has a power hungry high torque in there which is the cause of the "problem" (there have been cases of motor failure off the bat but the odds of that are slim to none so I would forget about it), the 25C is powerful enough to tick it over, the 15C isn't.

Checking the shimming etc might get it to work with the 15C, but as above, I would be prepared to get another 25C (cheaper than a new motor).

Might be worthwhile borrowing another motor from a spare gun (assuming you have a spare with the same motor length and the motor is man enough) that ticks over with the 15C ok, then stick it in the "problem" gun and vice versa for verification. If the "borrowed" motor ticks over ok in the DMR box - then its a hungry hungry high torque, if the borrowed motor has difficulties as well however, then the problem obviously resides in the gear box setup. (only suggest this because it is probably quicker to swap motors over rather than take the box apart and reset it up)

 

- Just for clarification with the mAh - that isn't directly the cause here, its the C rating (C rating dictates more or less, peak discharge - bigger C rating, the higher the maximum discharge) that's the problem, the mAh is basically the storage capacity of the battery - the larger the mAh the longer it will last.

(Actually it's a touch more complicated than that, mAh does affect the max discharge rate, but with only a 400mAh variance between the batteries it's inconsequential, next to the relatively huge difference in C rating)

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As the gun is new I'm guessing then that it has a power hungry high torque in there which is the cause of the "problem" (there have been cases of motor failure off the bat but the odds of that are slim to none so I would forget about it), the 25C is powerful enough to tick it over, the 15C isn't.

Checking the shimming etc might get it to work with the 15C, but as above, I would be prepared to get another 25C (cheaper than a new motor).

Might be worthwhile borrowing another motor from a spare gun (assuming you have a spare with the same motor length and the motor is man enough) that ticks over with the 15C ok, then stick it in the "problem" gun and vice versa for verification. If the "borrowed" motor ticks over ok in the DMR box - then its a hungry hungry high torque, if the borrowed motor has difficulties as well however, then the problem obviously resides in the gear box setup. (only suggest this because it is probably quicker to swap motors over rather than take the box apart and reset it up)

 

- Just for clarification with the mAh - that isn't directly the cause here, its the C rating (C rating dictates more or less, peak discharge - bigger C rating, the higher the maximum discharge) that's the problem, the mAh is basically the storage capacity of the battery - the larger the mAh the longer it will last.

(Actually it's a touch more complicated than that, mAh does affect the max discharge rate, but with only a 400mAh variance between the batteries it's inconsequential, next to the relatively huge difference in C rating)

 

C is not a discharge unit.

Discharge rating is measured in A.

 

12, 15, 25c etc alone is meaningless.

 

Your common 1500mAh stocktube battery is rated for 35A+ burst discharges (which all airsoft discharges are).

A normal 400fps 30rps rifle draws 20-25A.

 

If you cannot pull a 440fps DMR, don't change the battery as a solution (altough it's the easiest) :<

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I am aware C is not a discharge unit defacto, however it is the largest contributing indicator towards it mAh aside. The "easy" and broad calculation for max discharge is the C rating multiplied by the capacity and adjusted to a convenient unit (amps rather than milli amps), naturally it isn't exact but it gives a good broad indicator.

 

All I was attempting to say was that a higher C rating with a comparatively similar capacity will increase the max discharge the battery can handle - which feel free to correct me if I am mistaken, is the case.

 

Increasingly high torque motors require a larger current to get them to tick over (they wouldn't be higher torque otherwise) SRCs are a good example of this. The only way to get such motors to run at "normal" cyclic rates is to induce either a proptionally higher potential difference or a higher discharge rate across the terminals, which defacto means a bigger (more powerful) battery - in this instance the voltage and capacity being the same, means a higher C value is required. It has little to do with the setup of the gearbox in these cases, and is the only solution bar swapping over the motor for something with less torque.

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Parts list? I have a P* equivalent of your Mod 0 (posted in its AEG form before I swapped the stock out).

 

Cheers,

Piano

 

Systema 2009 SCK M4A1

Systema Red Cylinder 520 fps

Systema 12V Batteries

Empire Airsoft Hop Up Adjuster

Airsoft Surgeon 18" Steel Outer Barrel

Airsoft Surgeon Anti-cant Device

King Arms PRI Flip Up Front Sight

King Arms OPS INC 12th Model Supressor

King Arms Quick Detach Bipod Mount

King Arms Harris Style Spring Loaded Bipod

Prime WA/PTW Gas Buster Charging Handle

G&P SPR Type PTW Grip

G&P UFC Railed 30mm Scope Mount

G&P Leupold M3 Illuminated Scope Replica

G&P OPS INC SPR Flash Hider

PRI Gen III Free Float Carbon Fiber Hand Guard

ARMS #38 Swan Sleeve

ARMS #40 BUIS

MAG 160rd PTW Magazines

Tackleberry Upgraded 490A Motor

Tacleberry waterproofed Electronics

PDI 04 Tighbore Inner Barrel

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No, you (or others for that matter) did not indicate that in your posts. You talk about going from 15c to 25c.

 

C rating means little to us airsofters. It's a complicated thing about standardized testing for the manufacturer. When determining the product during their R&D, they use some different ideas than airsofters do.

 

You get back the A discharge rating by multiplieing the Capacity in ampere with the C number.

The C is short for Capacity.

25C is 25 * C, or 25 * 2 in case of a 25C 2000mAh battery.

 

You can write 7,4v 2000mAh 25C or you can write 7,4v 50A, but you can't write 7,4v 25C.

25 times Capacity only works if the capacity is also stated.

:)

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