What weight bio BBs for my GBBR?

[Defender-90]

I have a PTS/Mega MKM. It's been modded a tad and does 450 fps+ on .20s, according to ***********.
Lately I've been noticing the groupings being a lot looser and initially considered that to be a a worn hop up, which it might well be. But. Before I go to the expense of having that done it occurs to me I should try heavier BBs first. I've tried .28s and don't really know if I discern much difference between those and my customary .25s.
Where can I get heavy bio BBs in .32 and higher? What weight should I aim for? Which brands are the most accurate/consistent?

[StargateP90]

Re: What weight bio BBs for my GBBR?

Depends what you want. DMR style .30s or higher but it will get expensive. As a rule of thumb I believe all GBBRs should use .28gs as standard.

[Boo-Sabum Ben]

Re: What weight bio BBs for my GBBR?

Any particular reason for using Bios? As this will severely limit what you can use and the results you will get

[W0lf]

Re: What weight bio BBs for my GBBR?

If you're using the same bb's and have noticed a drop in accuracy then that would point to the hop rubber (which is cheaper to replace than a bag of bio's. unless you need to use them, I would personally steer well clear of them. And use .28. You can get away with .25 but for whatever reason (I assume their huge over volume due to the gas expanding) mine don't like .20

[GiantKiwi]

Re: What weight bio BBs for my GBBR?

Depends what you want. DMR style .30s or higher but it will get expensive. As a rule of thumb I believe all GBBRs should use .28gs as standard.

IMO anything based off the KWA LM4 system ideally needs a minimum of 0.3's, some weird performance fluctuations occur on lower weights (tested with 3 standard LM4's, 2 PTS MKM's and sort of relevant..2 PTS Masada's)

[Tariq182]

Re: What weight bio BBs for my GBBR?

My 416 DMR build overhops 0.3g. 0.28g and above should do nicely.

Depends on you fps for what weight. Mine still shoots 0.3g bbs at 330fps. You'll find bit of joule creep with GBBRs.

[Defender-90]

Re: What weight bio BBs for my GBBR?

Yes I think I have seen a decrease in accuracy on .25s. That said I'm starting to realise I should have been using .32s at a minimum from the beginning.
I'd like to use bios as I'm lucky enough to have 7 acres to shoot on and I'd prefer to minimise the chance of future generations of animals accidentally ingesting plastic. However heavyweight bios don't seem to be in great supply so I'll just have to scratch that and go with normal BBs.
I firmly intend to explore BB possibilities before jumping to any conclusions as, yes hop ups aren't expensive, but fitting them is as the MKMs inner barrel is a nightmare to disassemble and it'll need to go to a professional for that.
I also accept that even the best GBBR is less consistent than a cheap AEG, it's the price I pay for realism. Literally.

Being out of action due to foot in plaster and thus having nothing better to do than shoot out of the window and obsess over my toys, I'm going to give the hop and barrel a long loving swab out with alcohol and tomorrow will hobble down to my local shop and get whatever +.32s I can and load 2 mags with that and 2 with .28s and compare. Reckon I'll start at 15 yards and work my way up.

[JellyBelly16]

Re: What weight bio BBs for my GBBR?

Sorry to butt in on your thread. But what is the best weight should I use for a scar h gbb?

Cheers

[Defender-90]

Re: What weight bio BBs for my GBBR?

Sorry to butt in on your thread. But what is the best weight should I use for a scar h gbb?

Cheers

That would depend on make and if it's been modded. Part of my prob here is that mine's been modified a fair bit.

[Proffrink]

Re: What weight bio BBs for my GBBR?

Again, it's about what can be consistently lifted by your gun. Depending on the brand this can be as low as .25s or as high as .32s out of the box and obviously different hop up chamber/bucking/nub combinations will change this - heavier BBs will always shed energy slower whilst in flight than lighters ones, but the real limiting factor is money for many: No one is going to to be firing .40s+ automatic even in a flat hop or R-hop build because it's going to cost a pretty penny. Realistically for GBBRs I'd aim for .32s if you can and learn to not spam the trigger too much.

The key is consistency here as there are a lot of hop up buckings in stock chambers that can lift very heavy BBs if you turn it all the way up, but the cost is an inconsistent muzzle velocity, inconsistent backspin (i.e. hop) from the BBs smashing into a mound that's protruding into as much as 1/4 of the barrel (resulting in larger groupings and fliers). That's why a lot opt for R-hops, flat hops and will even go as far as to lengthen the chamber to apply that friction on the topside of the BB relatively gradually vs. a mounded bucking that you'll find in almost every stock gun.

Some CQB sites do ban certain higher weights because of how well they can hold that energy compared to a .20 or .25, so be aware of that. I've never been to a woodland site that's enforced such a rule though.

Again, golden rule is there's no real upper limit on what a particular gun can shoot so long as your hop unit is up to the challenge. To answer the questions though: Maybe start with a .25 then switch to a .30 and see if that goes well (perhaps even go to a .32 thereafter). Each will need the hop dialled in and a good 30 minutes or so of shooting so you can determine if it's consistently lifting those BBs and not generating fliers. You may also have the barrel surface to blame for inconsistencies (typically why people will concentrate on both the hop and barrel combination in tandem), but that's another story.

[W0lf]

Re: What weight bio BBs for my GBBR?

.28 and above for accuracy. It will fly slower than a .20 but a heavier bb retains its energy longer and is less effected by the wind. Depending on the fps anywhere between .28-.32 would be where I'd be looking. Unless it's high power (450fps+)

[Defender-90]

Re: What weight bio BBs for my GBBR?

Well I've got .28s and I'm not sure I discern enough difference to .25. So .32 is definitely on the agenda.
At the moment the gun is waaaay too powerful for games, but I do indeed have a weird yearning to use it "in anger" but first it has to shoot straight, so once I've got this sorted I shall consider an NPAS.

[Proffrink]

Re: What weight bio BBs for my GBBR?

The difference is super slight and akin to the old 'my gun can shoot 120 metres' problem (when it's pretty difficult for the naked eye to accurately judge distances over 20 metres to the kind of precision we need). You could get some measuring tape out to check (or just find a tree on the upper limit of your current ammo, mark where you are before switching and trying with the new stuff - taking steps back until you can't do it anymore) and you will most certainly be getting a range improvement over a .25 so long as your hop is correctly set, but it'll be hard to tell immediately for sure.

I agree though: .25 to .28 is negligible; I never use anything over .32 anyway because it gets very expensive very fast and the performance differences continue to be slight. I have used .40s in semi-auto builds though, but again the key is consistency and GBBRs fail at that all the time because the power source can be really naff in the wrong weather or without sufficient time between shots to let the magazine warm up a bit. Doesn't matter what BBs you're using or what hop up chamber and bucking combination you have: If your gun is flicking between 0.8J and 1.1J because the gas is cold then that BB is not going to hit the same place twice in a row.

I've been where you are with the NPAS. It helped a lot but ultimately I bit the bullet and went to HPA a year after installing it because UK weather just ruins the fun of green/black/propane powered GBBRs. If you're really having issues with consistency after looking into the barrel, hop unit and ammo then next stop is the power source. Daytona Gun, Tippmann or an HPA magazine tap are basically the only reliable options at that point. CO2 is a decent stop-gap but even it can feel the cold weather and cooldown. I should also prefix this by saying I was using a pretty old design (G&P WOC) with a very heavy bolt, which certainly didn't help.

[StargateP90]

Re: What weight bio BBs for my GBBR?

Sorry to butt in on your thread. But what is the best weight should I use for a scar h gbb?

Cheers

.28gs.

[callumbagshaw]

Re: What weight bio BBs for my GBBR?

Again, golden rule is there's no real upper limit on what a particular gun can shoot so long as your hop unit is up to the challenge

Just echoing what prof said.
If your hop isn't limiting you, then your wallet might.