SmallCaliberCentral

Has anyone AI'd a 204 yet?

This question has been beaten to death ad nauseum here and elsewhere.

The bore to case capacity is already past max for optimum performance, so an increase in powder volume will result in very small velocity gains. Read the material on this subject by John Barsness and P.O. Ackley. To 'improve' the 204 is an exercise in flushing money down the proverbial toilet. The small gains in velocity is greatly outweighed by the sheer amount of powder required to do so.

It's just not worth the time, money or effort. But it's your call.

I knew there was a reason I hadn't seen anyone do it. Wasn't thinking how overbore it already is when I posted a 2am

Read the 20 Caliber Cartridge Guide over on AccurateShooter.com. That's the ole 6mmbr.com. You'll find several 20 caliber alternatives.

Ya' know, it's been years since some of these type topics have been discussed. Might be worth repeating some of them for those who weren't a part of the original conversations..

https://www.accurateshooter.com/cartrid ... 20caliber/

Had a buddy that improved his 204 Savage and about all that accomplished was a burned out barrel. I believe he was running it to about 4200. There was no improvement in accuracy.

Ken158 wrote: ↑Tue Mar 02, 2021 9:53 amHad a buddy that improved his 204 Savage and about all that accomplished was a burned out barrel. I believe he was running it to about 4200. There was no improvement in accuracy.

Thanks for posting that, Ken. Glad someone with knowledge of actually doing it chimed in. It's exactly what was predicted and why it is not recommended, even by Ackley aficionados, including myself.

Hello; I shoot a 20 x 222 Mag improved, 40* shoulder. It should be quite similar to a 204 improved. I shoot one in a Rem. 788 that I tried to modify the clips to feed out of. That did not work because of the shoulder angle and minimum body taper. Ended up converting to single shot push feed.
Also shoot one in a Ruger #1, and of course it is a finger push feed. I find the cartridge to be very accurate and will push a 36 grn. bullet in excess of 4,000 fpm both rifles. Loads are with in 1 to 3 grains of the 204. I have several hundred rounds in the 788 barrel, accuracy is still good, but would think that the throat is eroding as most all throats do over time. I have no experience with burning out a 20 caliber barrel, but would think that an improved 204 would not be any more of a barrel burner than a the 204. As to the merits or lack of, improving the 204. Would I improve the 204R cartridge? probably not due to cost versus very little gain. On the other hand, would not give up the two rifles in improved cartridge I shoot. Hope posting my experiences helps and I say if it is something you really want, go for it.....

Why not talk to a gunsmith and have them set the barrel back enough and just run a reamer in cleaning up the worn throat and keep the 20-222mag cartridge ? That way you are all set up with brass, dies, etc.

The AI shoulder to limit case growth is the main point. Case capacity gains are pretty moot point, unless a real radical change is made.

I have tossed around the idea of a “different” 20. Use 223 Lapua brass, push the shoulder back to lengthen the neck a bit, then what ever sharp shoulder degree you desire.

Just to easy to run with factory brass though. I have found enough powder bullet combos to get to and over factory speeds.
Barrels are like tires, they are a wear item and can be replaced when needed. Take care of either and the tend to last a good long while.