This is the standard 5 1/2 inch barrel, and I believe all the magazines for these are 10 rounders, but I can check. You can actually purchase just the barrel for these if you wanted to be able to have it in both the 5 1/2 and the 7 inch. Personally, I have tried both as my best friend has the 7", and I just didn't find any need for it. Because of the heavy "bull" style barrel, the 5 1/2" was easy for me to place shots and even spin the little targets at 50ft. The 7" barrel just added weight, and didn't do much else for me.

If you have any more questions then please do feel free to throw them out. Thanks again!