How light of load can I go and still cycle the slide on a Sig P220 10mm?

[kmcdonou]

Long time lurker.

I am thinking about developing a lighter load for my Sig P220 10mm SAO for my wife, just to see if she likes shooting centerfire cartridges, as that is the only platform I have at the moment. She has only shot rimfire previously. Her hands are pretty wore out from massage work for many years. I have 180 and 200 grain cast bullets. Before I start with load development, anyone have a good idea of how low in FPS I can get before I get FTF?

I did look at some loads and was thinking something in the 40 S&W range using Accurate #5. I would love to get a load around 850 fps, but think that will be too low with a 24# recoil spring. Just curious if anyone has tried this and how low they got. It will reduce some time on my part.  Thanks much.

[Kenk]

Welcome kmcdonou,
I am not sure how low of a charge you could go, but a 10.4gr Blue Dot load with a 180gr XTP, or HAP bullet is not only incredibly accurate, it is also very controllable. If you can get past the BD flash in low light conditions, it is a very nice load. In addition, BE-86 may be something to look at. As for your P220, my stock Sig P220 Hunter functions perfectly with the 10.4gr BD load
The best of success on your wife's loads
Thanks

Ken

[kmcdonou]

Ken,

I assume you don't have chrony?  Alliant shows a 180 GDHP at 11 grains of BD going 1295 fps.  Are you thinking you are getting around 1,000 fps?

[The_Shadow]

kmcdonou, Welcome to the forum... Low velocity/Low pressure rounds FTF has a lot to do with the recoil system.  You might need a lighter recoil spring for better function...
Using a faster burn rate powder would be a good choice for better burning characteristics and cleaner burns.  Loading at 40S&W powder charges and using 10mm case with the longer COAL will yield lower velocity and pressure.
Lighter bullets will also help with recoil management.  That being said...
With Accurate #5 you might want to try the following:
180 grain bullet over 6.8 grains A#5
200 grain bullet over 6.2 grains A#5

[therognp]

Accurates data with AA#5 is 7.5 gr with a 175gr cast bullet or 7.8 gr with a 180 gr Hornady jacketed. Velocities are suggested to be in the 1025-1050 range.  And as suggested a lighter recoil spring might be needed.
On the other hand if she is just going to try shooting the P220, if its functioning as a single shot semiautomatic that may be just fine for the trial stage. Recoil springs for the Sigs seem to be more complex and expensive than for many other SA. Wolff does not think the P220 exists as far as their springs go

[Kenk]

Afternoon kmcdonou,
You are correct, I do not currently have a chrony, however 10.4grs of BD seems very tame in comparison to the Underwood loads I normally shoot; I apologize for the confusion

Ken

[kmcdonou]

Accurates data with AA#5 is 7.5 gr with a 175gr cast bullet or 7.8 gr with a 180 gr Hornady jacketed. Velocities are suggested to be in the 1025-1050 range.  And as suggested a lighter recoil spring might be needed.
On the other hand if she is just going to try shooting the P220, if its functioning as a single shot semiautomatic that may be just fine for the trial stage. Recoil springs for the Sigs seem to be more complex and expensive than for many other SA. Wolff does not think the P220 exists as far as their springs go

Yeah I was looking at that load, but it is a little higher fps than I prefer in this situation.

The recoil spring for the P220 10mm is interesting issue. It is only sold as a captured recoil assembly with the guide rod. I haven't tried to remove the guide rod cap and replace the purple colored spring with one of a different spring weight.  Someone on the SigTalk forum used HP38 to get a 180gr cast bullet down to 872 fps with no problem cycling the slide. He also reported having a 24# recoil spring in a Sig P226 40 S&W, but that seems a high spring weight for that model. I am not sure he was right on that.

kmcdonou, Welcome to the forum... Low velocity/Low pressure rounds FTF has a lot to do with the recoil system.  You might need a lighter recoil spring for better function...
Using a faster burn rate powder would be a good choice for better burning characteristics and cleaner burns.  Loading at 40S&W powder charges and using 10mm case with the longer COAL will yield lower velocity and pressure.
Lighter bullets will also help with recoil management.  That being said...
With Accurate #5 you might want to try the following:
180 grain bullet over 6.8 grains A#5
200 grain bullet over 6.2 grains A#5

Yeah, those look like good loads to me as well. My guess is they will be right in the ballpark of my desired fps when using the longer COAL of the 10mm.  I am hopeful those will cycle well.

[cgreth]

In my SAO P220, I run a 180gr polymer coated bullet (Bayou Bullets) with 6.0 grains of Power Pistol.   These are very accurate, always cycle the action and pretty light recoil.  I don't have a chronograph, so I can't say anything about fps.

[sqlbullet]

In my SAO P220, I run a 180gr polymer coated bullet (Bayou Bullets) with 6.0 grains of Power Pistol.   These are very accurate, always cycle the action and pretty light recoil.  I don't have a chronograph, so I can't say anything about fps.

I would guess that load is in the 800-900 fps range.