I had a little time on Sunday some more serious measuring of the RIA 45. In short, this pistol weighs 47.3 ounces and I need it to be under 43 ounces to be IDPA legal.
One bit of good news right off. The included full length stainless steel guide rod weighs 1.6 ounces. The standard guide rod from my Colt 1991A1 weighs 0.4 ounces. There’s 1.2 ounces essentially for free. The RIA with the standard guide rod and otherwise in IDPA equipment check condition came in at 46.1 ounces. 47.3 – 1.2 = 46.1! I love it when math works.
Not all the news is rosy. I thought the mainspring housing on the RIA pistol was steel and I had hoped to save a fairly significant bit of weight with a plastic part I had removed from the Colt. Unfortunately, it already has a plastic mainspring housing, so I will have to look elsewhere for 3.1+ ounces to trim.
The next big place to lose some material is under the grip panels. The frame is cast chromoly steel, 4140 to be exact, with 100 percent coverage under the grip panels.
This is a strong steel and I believe I can safely skeletonize this area of the frame without compromising the strength of the pistol.
This is very preliminary scribbling. The cross bar is an optional piece that I may elect to leave. I won’t know exactly how much weight this will remove until it is cut, but back of a napkin calculations look promising.
4140 weighs 0.284 lbs per cubic inch. The slabs to cut out are about 1 x 3 inches and the material is (from memory) about 1/10 inch thick. So…
2 cuts x 1 x 3 x 0.1 cubic inches x 0.284 lbs per cubic inch) x 16 oz / lb
2 x 0.3 x 0.284 x 16 = 2.7 oz
Because of it’s complex shape, calculating the weight of the cut off end of the dust cover is not quite as easy, but if it is 1 oz or more, I’m done.
If my math is questionable and if after all of the above the pistol is still overweight, I can carve on the magazine well funnel. This part is 2.7 ounces by itself, though discarding it would not look right and might draw undesired attention at the equipment check stage of a major match. However, the funnel is far beefier than it needs to be and I think I could carve enough out of it to help and it would probably look better. It has some rough and bulky edges. Some blending would look better.
When all this is done, I should refinish the pistol or at least the frame and magwell funnel.