Need help with BB weight choice, new aeg build

Alright:

~4 isn't terrible but it could be better. It's difficult to tell what exactly is the limiting factor. My first suggestion is to use a piece of cork or even a piece of plastic as a buffer between the hop unit and the upper receiver. This will provide more consistent pressure than even a strong spring.

Springs are very important--an M120 with great airseal should put you between 1.4 and 1.6 Joules depending on your setup. PDI and Guarder are the highest quality easily available in the USA, with Guarder being far more prevalent. Many, if not most springs sold to the American market are actually soft, and will lose power and even physically bend, causing extra wear and less-than-ideal consistency. These include Matrix, SHS/Rocket, Core, and many other common brands. I have heard ASG and Prometheus are also good quality, but haven't had anyone experienced confirm with good chrono results. For reference I usually push for ~1 FPS.

Check if your hop arm is wiggly before shimming--tape works great. Stabilization in general is very DIY. As long as it works it works! I typically use wraps of ordinary Scotch tape on inner barrels, and then aluminum tape on the hop arm "wings", and cork between the hop unit and upper receiver, or some other rubbery material.

I like the Modify flathop rubber. What nub are you using?

The cylinder matters quite a bit in this case--for those .43gs and a full cylinder, you only have enough air for about 300mm of barrel length. With that V2 cylinder you may be seriously undervoluming your setup and causing drag on the BB, which would reduce accuracy.

Ok, here is what I got:

Fps measured with . 43
302.4
304.4
303.2
300.0
302.5

Bbl length (inner) is about 15.5 inches. Sounds like I am about 3 inches long....? What should I drop bb weight to. However the .43 are more consistent than .30s. Maybe the weight factor has more input? Should be a sweet spot between. 30 and .43.....

Spring is made by "Rocket". Any good?

No nub, krytac flat arm pushes directly on hop rubber

Thanks much!!

I'd say that 60m body hits, say 3/5 shots is probably a pretty solid goal in good conditions for a gun like that.
I'd maybe take a look at .40g or .36g BBs instead, and depending how much you plan on shooting I may suggest that you get ASG brand BBs in the small 1000rd bottle as those have proven to be the best BBs stateside, at least the ones in .48g I purchased.

As for your barrel, if it is not aluminum I would very highly recommend that you lap it after taking a look at the lapping guide in my signature, as that will very often improve accuracy by 30% or so in two cases I have tested.
I think that it can probably be done for sub $35 and in under an hour and a half if it's your first time doing it.

The other improvements I would recommend would be replacing the spring on your barrel with a stack of O-rings instead, and inserting a sleeve made of soda can, playing card, or paper into your muzzle between your inner and outer barrel in order to align everything. If you can, I would also recommend doing so a couple inches from your hop chamber, and once you are sure that it fits you can super glue the shim material to your inner barrel.

Spurgeons Hammer said:

Ok, here is what I got:

Fps measured with . 43
302.4
304.4
303.2
300.0
302.5

Bbl length (inner) is about 15.5 inches. Sounds like I am about 3 inches long....? What should I drop bb weight to. However the .43 are more consistent than .30s. Maybe the weight factor has more input? Should be a sweet spot between. 30 and .43.....

Spring is made by "Rocket". Any good?

No nub, krytac flat arm pushes directly on hop rubber

Thanks much!!

Click to expand...

Rocket are SHS but with a bit better QC. I would personally say drop the Rocket and go for, say, a Guarder, but that FPS consistency isn't horrible, and if the up-and-down consistency doesn't bother you than it's a minor improvement. It is likely that the Rocket spring will lose power over time a lot faster than it should, but as long as it's not the silver version you should be okay. I've had the silver versions bend inside the gearbox and cause early wear on different parts due to shoving the piston around.

That's about a 400mm inner barrel, so definitely undervolumed... If I were you I'd at least purchase and try out a full type 0 cylinder, which should be pretty cheap and easy to install. If your power goes way up, you know it was lack of air. Ideal barrel length (on a full cylinder) is around 300 for .43g and 380 for .30g. If I were you I'd go 363mm to split the difference, or just stick with your current barrel, try out a full cylinder and see what you get.

Your Krytac arm is probably fine, but if you wanted to try making a flat or concave nub out of some scrap plastic it's a dirt cheap way to try and improve accuracy. Basically just an interface between the arm and the rubber to try and provide more consistent, flatter pressure.

Personally, using .43g, I would aim for better consistency (say, at least headshot consistency at 60m), but work towards your own goals. I build rifles based on what works well on my field, but not everywhere is the same.

I'll second SiliconeSword's suggestions. He spends way too much time figuring these things out...

OK, I have to comment on the issue of price for heavy weight BB's, and the hesitation of people to step up to heavier weight bb's.

Yes, the heavier do cost more, per shot; but cost is also a metric of consumption. Let's say that we engage a target that is 200 feet or so out (numbers are from the hip but demonstrative of observations that I have made in the past:

• It takes ten shots of .32g BB's to hit that target
• It takes six shots of .36g BB's to hit that same target
• With .40g BB's, the target is hit with the fourth shot
• Using .43g BB's, the target gets hit on the third shot

If the cost of .40g BB's, per shot is twice what the cost of a .32g BB is per shot, it's going to cost a player 8/10th's (or 80%) of the cash outlay, to use .40g BB's that it versus what it would cost for the use of .32g's. In the end, its extremely likely that a person is paying more to use .32g BB's than it would for .40g's (similar math can be done for comparison of other weights)