Supported vs unsupported chamber for 1911

I am a brand new BE shooter and my first goal is to get distinguished with a pistol. I picked up a 9mm 1911 SA RO to get started. Accuracy is not great compared to the custom built 1911 .45 I used to shoot for the USMC. Consequently, I plan to send the RO to Springfield to have a match barrel fitted to slide and with a bushing. One of the options is to have this service with an unsupported chamber or a supported chamber. Supported option is $100 more.

What is the difference between supported vs unsupported and which option would I want in a 9mm 1911 for BE competition ?

Thanks,
-Trevor

Your replacing the barrel or just the bushing?
My SA 1911 9mm shoots fine with just a bushing.

I plan to replace the barrel AND bushing so I can have the barrel lugs fitted to the slide for tighter lockup.

-Trevor

I found some pics that helped me understand the difference between supported vs unsupported. From what I read, unsupported is only appropriate for standard .45acp loads. In my case, a 9mm fits into a category of higher chamber pressure and a supported barrel is required, yes?

Anyone loading 9mm for their 1911? Do you have to load the 9mm slow to shoot well at 50yd like the .45acp?

-Trevor

The difference is $100, just like you said, they shoot the same. Unless you are trying to make major power factor it's unnecessary.  Don't send it to SA.
In their opinion you already have a match barrel.

There are several members of this forum who have a better understanding of what you want to achieve and the skills to get you there.

If your sending the (9mm)RO back to Springfield or anyone for that matter you have zero options on what you want. The frame already has a Wilson/Nowlin cut for a supported barrel. Trying to put a non supported barrel leaves a major gap. 

Len

If you’re a reloader, (and who the hell in this game isn’t) you should opt for a supported chamber.  Especially in 9mm.  Some of the “accuracy” loads are up there in velocity and pressure.

As Len said, your pistol receiver is already cut for the Wilson/Nowlin ramped barrel. You have to stick with that barrel type. Both Kart and KKM make appropriate barrels.
Jon

Ok, I now it is obvious that it has a supported chamber and I have no other option but to stay with that feature.

Thanks everyone,
-Trevor

Hengehold, the good news is that you won't have to spend the extra 100.00. That fee was to cut the frame for a supported barrel. The barrels cost the same either way.

Len

I use predominantly KKM barrels when building ball guns. I highly recommend their barrels. The RO will make an excellent competitive  pistol.
Jon

Jon, For ball matches, what twist, recoil spring, and trigger weight do you set 9s up for?

Thanks

Owner of pistol determines the twist rate based on bullet preference; I use both 16 and 32 twist. 
Because barrel is match fit 10# recoil spring. For ball guns I sometimes provide extra sear spring so pistol can be used for CF matches with 2.5# pull and 4# spring for EIC matches.
Jon

The long time members of the forum know that I am a huge advocate for Springfields as the base for a bullseye pistol, but I would NOT recommend their custom shop to accurize one.

I would consider:
KC Crawford
Dave Salyer
Jon Eulette
Will Newton (Paper Puncher Gunworks)
FPK Precision (Paul Fisher)

There are others that I'm sure others will mention, but I must emphasize that you should stick with builders who are experienced in building for bullseye like the ones I named. Springfield just doesn't focus on the same things that the others I mentioned for a successful outcome.

-Rob Kovach
Administrator
www.bullseyeforum.net