Duplicated UW 45 Super

[Alaska]

Duplicating the Underwood 255gr in 45 Super

8.2 of Longshot
250gr Rim Rock RNFP Top Shelf
WLP Primers
Starline 45 Super Brass
1.220”
Lee Factory Crimp
1075 FPS

5.2” KKM and 24 pound Spring
G21 Gen 4

 

[Guy Miner]

Thanks for that report. Am very interested in the 45+P and 45 Super.

Guy

 

[Alaska]

Thanks for that report. Am very interested in the 45+P and 45 Super.

Guy

Going into my 3rd year with 45 Super in G21.
using my G21 more than G20 in Bear Country of Alaska.
The 3 powders I have used so far are Power Pistol / Longshot and AA9.
I have a Rowland Comp that I used in testing only with 45 Super + P loads. Easy with those 3 powders . Prefer No Comp
Enforcer Powder is one I would like to try also with CCI 350.
My best loads so far has been with Longshot and the 250gr Rim Rock TS RNFP. I noticed in KKM barrels the regular WW and Starline 45 ACP brass performed excellent at 45 Super + P levels.
I prefer WLP primers for 45 Super and 1.220” with Longshot. Same as UW but I think they went back to CCI 300.
My 45 Super load is 8.2 of LS with this bullet which is 1075 fps in 5.2” KKM . I don’t need more velocity for Bear Protection that’s plenty.

I have some Starline 45 Super Brass on hand but after testing with regular 45 ACP I see no need for it in KKM barrel. .481” is Max case expansion don’t go past that on brass. Using my KKM barrels I have not even come close to .481” with velocities closer to Rowland than Super.

Power Pistol @ 8.6 (Fed 150)
Longshot @ 8.2 (WLP) Favorite
AA9 @ 12.6 (CCI 350)
5.2” KKM 1075 FPS No Comp

Done some testing with 45 ACP Fed Nickle Small Primer Pocket using CCI Small Pistol Mag primers excellent results very nice primer results with PP and LS very similar to 450 SMC using Missouri 255gr Keith .

Duplicated BB load with 255gr Hardcast 45 ACP+ P
AA9 @ 12.0
CCI 350
250 Rim Rock TS RNFP
1.190” same as BB
45 ACP Starline Brass
990 to 1000fps in 5.2” KKM
BB factory load is 958 FPS in 4.6”’
11.8 of AA9 should land you dead center on BB load and BB 255gr Hardcast bullet is closer to 250gr in weight than 255gr. Possibly the same Rim Rock bullet that I use !

Tamper Crimp all .471” with Lee Factory Crimp Die.

 

[Guy Miner]

BTW, I've decided to keep my 45 1911's at no more than 45+P levels and call it good at that. Others may wish to take them farther. That's fine.

If I need more power in a handgun, I'm pretty doggone competent with my 44 magnum revolvers.

Many will disagree, but at 70, probably within the last 10 years of my life. This is where I stand and am not going to push the 1911 any harder.

Regards, Guy

 

[Alaska]

BTW, I've decided to keep my 45 1911's at no more than 45+P levels and call it good at that. Others may wish to take them farther. That's fine.

If I need more power in a handgun, I'm pretty doggone competent with my 44 magnum revolvers.

Many will disagree, but at 70, probably within the last 10 years of my life. This is where I stand and am not going to push the 1911 any harder.

Regards, Guy

Several modifications for 1911 Steel frame for 45 Super.
1911 45 Super Upgrade

Wilson Combat Parts for a .45 Super‑Ready 1911

Below are the exact 5 Wilson components that matter, why they matter, and which ones are optional vs. mandatory.

---

1. Wilson Combat Heavy Recoil Spring (22–24 lb) — Mandatory

Part: #10G22 (22 lb), #10G24 (24 lb)
Role: Controls slide velocity and reduces frame battering.
Notes:

• Most .45 Super 1911s settle at 24 lb for full‑power loads.
• If your gun struggles to return to battery, drop to 22 lb.


---

2. Wilson Combat Flat Bottom / Small Radius Firing Pin Stop — Mandatory

Part: #7B (Bullet Proof FPS)
Role:

• Delays initial slide movement
• Reduces lug stress
• One of the most effective upgrades for .45 Super control


This is a must‑install part for any high‑pressure 1911.

---

3. Wilson Combat Heavy Duty Firing Pin Spring — Mandatory

Part: #26 (Extra Power Firing Pin Spring)
Role:

• Prevents primer flow
• Prevents inertia firing under heavy recoil


---

4. Wilson Combat 23 lb Mainspring — Mandatory

Part: #417 (23 lb)
Role:

• Adds resistance to slide opening
• Reduces lug stress
• Works with the FPS to slow the system down


This is a key part of the “delay the slide” strategy.

---

⚠ 5. Wilson Match Combat Ramped, Fully Supported Barrel — Mandatory if your gun is non‑ramped


Part: #33 Series (Nowlin/Wilson ramped barrels) Wilson Combat 1911 Match-Grade Drop-In .45 Barrel 5" Full-Size
Role:

• Provides full case support
• Prevents case blowout at .45 Super pressures

The Glock 21 is much simpler for upgrade for 45 Super …..KKM Barrel / 24 pound spring / Wolff Extra Power Mag Springs.