New M4 out the box, 170 FPS.

[MuPPeT_ON_TouR]

Hi,

Brand new out the box M4, my first RIF so wanted to keep it basic.  I will be the generic M4 player for a while.

This was 1 of three RIF's bought via Evike. An M4 for me, and a AK and an AUG for my sons, the AK and M4 took just over 5 weeks to get to me from the US via France to the UK...   These where absolutely the RIFS's we wanted, and I mean the way they look.  We did over pay but buy once and cry once was my thought here, at least if they look right then anything else can be fixed or repaired....  or upgraded.

As the title says the M4 was just 170 FPS for the first 8 shots.  I contacted Evike and to their credit they have since offered to take the RIF back for repair and perform an upgrade.  But the cost of shipping it back and the thought of playing with another RENTAL! on Sunday while my kids run around with their new guns made the rage start.  Three games with rentals to get my UKARA was enough for me, besides that, before Evike replied I already took the orange tip off and the gearbox out so kissed good bye to the warranty ?

What I found inside was disappointing, the piston O ring swimming in sticky oil/grease so it couldn't expand and seal.   After that was cleaned it sealed inconstantly, air would leak past the cylinder head and was even worse when the nozzle was on.  The gears are also rusty and had no discernible lube on them...  I guess they stuck all they had on the piston head.  All the O rings seem dry/shrunk/flat and I suspect this RIF has been sitting about for a while, but this is only a suspission.

Long story short I reached out to the guy from AK2M4 and was very happy with how fast he replied and didn't try and sell me 100's of new bits I didn't need, he recommended new seals, clean up the gears, lube them and a couple of other things that were inexpensive, it was only after I pressed him for upgrades he obliged my desire for shinny new bits with some recommendations.

I have on the way:

POM piston head, don't like the thought of aluminium ones scraping down the cylinder.

Aluminium Double seal cylinder head, it come with a plastic one

Double seal nozzle, 2 is better than one

New cylinder 4/5th, the RIF come with a full cylinder and only a 320mm inner barrel.  I understand there is an air to inner barrel ratio, but not learned the specifics yet.  The inner barrel is also a bit bent, rolling on a flat surface and a torch shows more light coming under from the hop up end, I did plan on a new barrel and have an excuse now but that can wait till I have at least had a game with it, will see if the bend effects it to much.

The reason for the post is this is a lot more involved than I thought I would be with a new RIF, I figured I would learn slowly.  I will use this post to update and ask for help with any other problems I find.  Any help or advice as I try and fix the issues are welcomed and encouraged.

View attachment 111363

 

[Cannonfodder]

Wow, 170fps is very low. What brand was this?

 

[EDcase]

Sorry to hear of your troubles but its a good example of spending more doesn't always get you a better product.

Yes, curious to know the make.

The good news is that it should be easy enough to clean up and get back to the way it should be.

Use steel wool to clean the gears of rust.  (Be careful to remove and keep any shim washers) [Would be best to re-shim anyway]

Use Isopropyl alcohol to clean the grease off and get some new light silicone grease.

Might need a new O-ring for the piston if its old and hard.

AK2M4 is a great guy and you can trust whatever he recommends.

 

[MuPPeT_ON_TouR]

The M4 is EMG F4 Defence Licensed F4-15, I don't believe EMG make them but I don't know who does, does anybody?

View attachment 111376

Gear box is a Dytac Ver.2 QD 8mm w/ Acetech MOSFET.  The GB shell seems pretty good, but it's the first I have seen in the flesh so not sure my opinion counts for much.

To be clear when I say we overpaid, we overpaid for the looks, we were not overly concerned with the performance as I think all RIF's have issues with corners getting cut.  To my mind the performance can be fixed, mainly by throwing money at it, but the look of your gun can't.  I just didn't want people pointing out we could have got better for the money, especially seeing as mine has issues out of the box.  Performance wise they will be 100% correct, but I bought the RIF's I like the look of and was prepared to sort any issues, though I didn't think that would be on day 1. 

Not sure I'm ready for a shimming job yet.    Will fix the air parts first so I can at least use it, then move onto the inner barrel and hop unit.  Then finally look at GB and motor with an ETU, not going DSG but 16:1 or even 13:1 seems doable for me.

 

[Cannonfodder]

EMG stands for Evike Manufacturing Group. A very misleading name as they don't actually manufacture anything, just rebrand ACM guns which means QC can vary wildly

I bought the RIF's I like the look of and was prepared to sort any issues,

That's definitely the right attitude to  have

 

[Speedy Sloth]

Airsoft the only industry where QC stands for quick change and not quality control.

 

[MuPPeT_ON_TouR]

Because I can't leave anything along for very long I cleaned the barrel, I have been waiting on some polish and IPA.

Polish was used to remove oxidation this time only and not to "polish" the barrel, it was then cleaned with the IPA. 

Easy to see by eye but next to impossible to picture but there are ridges all the way down the barrel.  I'm pretty much set on buying a new barrel at this point but I don't mind finding justifications to make me feel better about it.

Are these normal? is it further evidence of poor quality?

View attachment 111384

 

[Fatboy40]

To be clear when I say we overpaid, we overpaid for the looks...

Other than the funky end of the handguard I'm seeing a Double Eagle M916 ? (but with substantially worse build quality, sorry)

 

[Leo Greer]

The barrel is difficult to tell. I would work out the other issues and make sure everything is clean and stable before judging the barrel quality. A quick polish can do wonders. DIY stabilization of the unit, hop arm, barrel, etc, will do even more. And a new hop rubber is cheaper and more cost effective than a new barrel (In general. A bad barrel will still ruin your accuracy even if everything else is great.)

POM piston head - good replacement. It'll be more durable than stock if you ever want to increase your power or speed.

Double seal cylinder head - nothing wrong with this, but it's worth noting that being plastic does not make a cylinder head bad in any way. The seal makes it bad or good. In fact, plastic cylinder heads actually deal with shock from the piston better and help you avoid gearbox cracking.

Double seal nozzle - this seal never comes into play. Whether the nozzle is actually better or not depends on how wobbly the stock one was on the nozzle tube. In fact, many "aftermarket upgrade" nozzles will have bad tolerances with various nozzle tubes (inconsistent specs) and be worse than the stock nozzle.

4/5 cylinder - for a very detailed discussion of cylinder volume ratios, head over to Airsoft Sniper Forum and start reading the "Long Range AEGs" stickied threads. For a quick explanation, there is no "best" answer here. If your cylinder has too little volume, you'll lose power due to barrel suck (vacuum forming behind the BB). However, if the cylinder has too MUCH volume, you lose nothing--the RIF is just louder. Ideal volume also depends on weight. Heavier BBs use up more air, because they absorb more energy to achieve the same velocity. For a 320mm barrel using .20g BBs, you could get away with a cylinder smaller than 1/2. However, your stock cylinder is just fine, as it gives you extra air, allowing you to run, say, .36g without losing power.

Overall, there's not much point to changing your full cylinder unless you're trying to quiet the RIF's barrel noise. This is not an exact science, and we have leeway on what voluming choices to go with, hence why most carbine length RIFs come with a 3/4 cylinder, which both sounds reasonable and allows you to run .20g-.30g from 300mm to 380mm.

As a general rule, anything Evike lists as theirs under "EMG" or their other house brands is bad or overpriced for some reason or other. Even the Cyma Platinum line, while in most cases excellent, has it's share of weaknesses, and inflated prices.

I actually own a similar RIF with much the same internals, except mine has performed excellently through the fire and flames. It's one of the older Dytac models without all the fancy branding and receiver design, but the meat and potatoes are the same. As this model of gearbox has been made for years, it's very possible you have a years-old gearbox in a much newer shell. Ah, gotta love airsoft QC and inconsistency.

You clearly needed some replacement o-rings on the cylinder head and piston head, but as a general note, testing compression with the nozzle on is a false test. Because pressure flows in one direction, an o-ring on the nozzle only comes into play in case of a blockage on the end of the nozzle. In this case, your finger. Otherwise, nozzles without o-rings seal perfectly fine (Krytac). O-rings were introduced because of bad tolerances between nozzle tubes and the nozzle causing wobble.

 

[MuPPeT_ON_TouR]

Thank you Leo, perfect insights for me and will defo follow up with the "Long Range AEGs" post and forum, will be some night time reading. 

The double seal cylinder head has the smaller/thinner of the rubber pads available I have seen so I hope will act as good as a plastic one for shock absorption, the plastic one had no pad.  The AOE was very far forward, 1 o'clock or more, so the pad will help push it back I believe, I will just shave down the teeth as necessary and leave as is.  Proper AOE can will till i get into the gearbox and learn more as mentioned prior.  The GB does have some healthy radiuses in the corners so I hope the shell will last.

The original nozzle was wobbly on the piston head and the tube it fitted over was tarnished and oxidised, I thought this was a factor of the O ring but will revaluate the nozzle to piston head tube bit fit when it arrives.  The air leaked when just holding finger over the tube bit with no nozzle fitted, it was worse with the nozzle in place.

The cylinder I will look forward to testing to see what noise/performance(Accuracy & FPS) differences there are if any.

The barrel and hop unit out the box was a bit ruff looking, the olive(brass O ring bit) was held in with what I now know is a kind of thread lock they used as a general purpose filler/glue.  Now I have cleaned it the brass ring just falls out and slides down the barrel...   Anybody know how to hold it in place, or where to buy the glue stuff?

For the bucking have have opted for the ubiquitous maple leaf Macaron and MR, hop and nub...  yes, I panicked and went for both...  I have three RIFS to play with so it will not get wasted.

View attachment 111397

I knew being Evike meant rebranded..  and there was an inherent risk.   But I really liked this design, It was hard to find another I liked the look of that would have had potentially had better QC ....  As much as we all know every M4 looks the same more or less, thanks to Fatboy40's insightful and helpful comments so please don't apologise.

Other than the funky end of the handguard I'm seeing a Double Eagle M916 ? (but with substantially worse build quality, sorry)

It was exactly the "funky end" that I liked with the M-Loc hand guard... and the more vertical hand grip and the more milled out receiver design and the 45 degree fire selector...  But he is right, all M4's look like the M916 and shame on me for not buying better build quality.

 

[MuPPeT_ON_TouR]

It works!   

Had to shave down one tooth a little as the AEO had changed a smidge.  Run a bit of 3000 grit over the inside of the port on new cylinder for peace of mind.  Used some Teflon tape over the hop unit/barrel washer to hold it in place.

Used many many 4 letter words directed at springs and I got 322FPS from an XT M95 spring, its only a 320MM barrel.  Will try bigger springs & a longer barrel when it arrives.

 

[MuPPeT_ON_TouR]

Swapped to a 430mm long barrel, hidden in the normal mock suppressor.  

M95   0.2g BB - NO HOP 334 FPS

M100 0.2g BB - NO HOP 361 to 365 FPS

M105 0.2g BB - NO HOP 388 + FPS

My field limit is 360 so settled on the M100 with hop sits at 348 to 355.

Does this look right or could there be sealing issues?

 

[Rogerborg]

Seal could maybe be better: I've seen a super-spicy 1.3J out of an "M100" spring, stock plastic CYMA piston/head/nozzle, and a 229mm ZCI barrel just by lucking out on the airseal.

What you've got is fine though, as long as its consistent - that's what really matters, rather than chasing 5m more ultimate range but being all over the place.

One thing though, you might see some Joule creep with heavier BBs.  I'd recommend chronoing with the BB weight that you intend to use, and some hop applied, unless your site is still chronoing like it's 1999 using 0.2g BBs.

 

[Leo Greer]

Could it be better? That depends on your spring, and a lot of other factors.

Setups are extremely individual here: port location, piston weight, BB brand, barrel wobble--all these come into play when determining exact FPS on a certain setup.

Additionally, most airsoft springs are not rated consistently in any way, shape, or form. Some manufacturers, like PDI, still hold to a quantifiable system, but many makers just slap labels on things. The springs are also inconsistently made, allowing inconsistency between springs of the same brand. I once got a 2J reading out of an "M120", which is ridiculous.

This means that your airseal could be perfect, or it could be bad--FPS alone tells us nothing, because we have no consistent baseline.

To test your airseal, you should first try placing a piece of tissue paper over the feed tube with the replica upside down, and dry fire a few shots in semi. If the paper blows off, you know your nozzle to hop packing seal is bad. If it doesn't, then your nozzle/packing seal is probably okay.

Another item is consistency. Using high quality BBs (G&G, BLS, etc), a well-built AEG can achieve less than ~1 FPS variance between shots in a series of five or ten. (FPS varies by humidity, etc, so FPS will naturally change slightly based on the day and the weather)

Finally, there are still makers that produce very high quality springs that are very consistent both in output, and consistency among themselves. Primarily, this is PDI and Guarder. There are other springs that are fine, of course, but these two brands have excellent track records on their springs, and I've recorded extreme consistency from both.

 

[MuPPeT_ON_TouR]

Thank you both Rogerborg & Leo

unless your site is still chronoing like it's 1999 using 0.2g BBs.

Yes, still 1999 up here.

Springs are all XT branded from AK2M4.

you should first try placing a piece of tissue paper over the feed tube with the replica upside down, and dry fire a few shots in semi. If the paper blows off, you know your nozzle to hop packing seal is bad. If it doesn't, then your nozzle/packing seal is probably okay.

Watched a few YouTube vids last night on nozzles to see if mine was ok and NOT ONE motioned doing this.  My nozzle makes what I think is OK contact with the bucking lips and it goes back enough to allow a BB to feed.  Will try the paper test and see what happens.

The 0.2g BB's I'm using come in a milk carton and are what was left over from our initial rental games.  I have purchased Warhead 0.25g to play with...  Will check for consistency with the .25 but as said my site chrono with .2's so will need to measure FPS off them.  Unfortunately my garden is just over 20m so I'm unable to set an accurate hop, I should be on the low side so will lose a bit more FPS when I get to set it at the field. 

As always thanks to all for the information and help getting mine working.  I still have my son's AUG and AK to look at but they both worked fine out the box, I have cleaned the barrels and given them a light polish..  As long as the weather holds then first game with no RENTALS is Sunday.

I will then look to change gearset to a 16:1 with a ETU added, when this is successful and stable it will be a semi locked DMR build on a SCAR H SSR, so need my M4 to be reliable and consistent.

 

[Leo Greer]

Sometimes it's the oldest, simplest tricks that get overlooked and passed by. For example, people think they need a MOSFET, when you can actually put dielectric grease on your trigger contacts and achieve the exact same thing way cheaper with none of the hassle.

As long as the consistency is good with your quality BBs, it's a good sign that the air seal in general is okay.

The XT springs look okay to me. I wouldn't trust them as much as Guarder or PDI, but they'll probably hold up fine.