[pwatts]

Hello so I am looking for some advice on parts and a base for a dmr. For my field it needs to be 450 fps or lower with semi only (no full auto option). I am open to all base guns and parts added on. So my budget is $300, what is your opinion on the best base gun and upgrades I can get for a 450 or lower fps semi only dmr? Thanks

 

[philbegas]

Your budget is for just the base gun or for gun+ upgrades? $300 is not all that much for a proper DMR

 

[philbegas]

That being said if I had a low budget I'd probably go for:
A&K Full Metal SR-25K Airsoft AEG Rifle w/ Crane Stock, Airsoft Guns, Airsoft Electric Rifles, A&K - Evike.com Airsoft Superstore
A&K Sr25 (extended gearbox so more cylinder volume to play with),
ZCI Inner barrel
I'm not an expert on which flat hop to choose but probably a new 70degree bucking, and a flat nub. (I'm sure other people can recommend better ones).
According to evike, the SR25 shoots at 400-450FPS with .2s so if you do some DIY on the compression you might be able to get it to be on the higher range of that.
For example maybe this:
Achieving 100% Air Seal in Your Gear Box

 

[Thenoobatsniping]

I would go for modify hard flat hop bucking.
You also may want to buy and full auto capable gun, and jst use semi at 400fps and see if you miss the full auto. I know I did. Also it's a big change from 0med to 100med (atleast at my field 450fps=100ft med) so you may want to run a 0med gun and just try playing with it like it's a 100med gun.

 

[CrusherW9]

I'd recommend just getting an AEG that shoots sub 400 and tuning it up first before dropping in a beefier spring. You'll be able to use it with full auto in the meantime without being at the disadvantage of a sub par DMR on semi. Get your compression system and barrel assembly sorted out first. Once your FPS is +/- say 3FPS and you're happy with the precision, drop in a heavier spring to get you as close to 450fps as possible and move up to quality .36g bbs. Improving trigger response would also be something to work on, though simply getting something like a ZCI or SHS high torque motor may solve that problem well 'enough'.

There's a ton of free/very cheap mods that can be done to improve the performance of a stock gun. I call it 'setting a good baseline'.

Basics (Do these first before doing any mods):
- Run a decent 2s or 3s LiPo
- Use Deans plugs
- Use quality .28g+ BBs
- Keep your barrel clean

If you gun doesn’t have them:
- Metal spring guide
- Metal bushings

Once the above is accomplished, move on to the little mods.

Inside Gearbox Mods:
- Re-shim your gears
- Re-grease gears and compression system
- Correct AOE
- Polish cylinder
- New piston head o-ring
- Teflon cylinder head
- Radius cylinder cutouts

Outside Gearbox Mods:
- Shim hopup arm
- Shim inner barrel and assembly
- Flat hop
- Teflon/Floss/Permatex bucking

From there, upgrade to accomplish the previously mentioned goals. You know, I've considered modernizing the 'Holy Grail' thread, but there is a ton of that information out there so I just assume it wouldn't be that useful. But maybe I'll do a write up on my version of that thread once I buy a used AK and I'll do a comparison from stock to tuned.

EDIT Again: After just now reviewing that thread, it seems pretty k. Maybe I won't.

 

[torkas]

Modernize Holy Grail, please.