I am not a gunsmith or expert but I will tell you what my FLG does in that direction. The limiting factor on slide recoil spring tunnel size is that it be long enough to contain the compressed spring so the slide is stopped by the tunnel on the guide rod flange against the abutment. You do not want the slide stopped by the spring "going soild." That has to be with a spring strong enough to take up the recoil and chamber a round.
My FLG greatly values the slide travel of the G.M. 5" So what he does is cut them off to 4.25". This requires:
1. Cut 0.75" off the slide.
2. Recut for the bushing lug (He doesn't like bull barrels.)
3. Shorten the bushing and barrel.
4. Reset front sight.
5. Turn barrel down to .580" (less bushing relief) back to the face of the second locking lug, removing the front locking lug. He does not consider that this reduces lockup strength, and points out how little engagement there is on the usual front lug.
6. Build a skinny recoil spring guide rod and plug with small hole to take a Glock flatwire recoil spring. (He now uses the ISMI flatwire spring in a higher rating.) Clip spring to the maximum number of turns the tunnel will hold without going solid.
He was also putting Glock springs in OACPs before ISMI came out with their package deal. It works there, too. No 300 round spring life limit. I think it would be just the ticket for a Kimber Compact, too.
They shoot well. Mine came about when I took the compensator off a gun which had had the slide shortened to make a IPSC Modified "Box Gun." It worked well so he chopped his own and has done others. An update of the old pre - Combat Commander Bobcat conversion, he calls it the Polecat.
It is way more expensive than a Commander with a relibility package though. I can't say it shoots any better, either, but it is for sure different. The main difference I see is that the cut-off GM ejects its empties in the same general direction as a standard GM while most Commanders and OACPs scatter them all over.
My FLG greatly values the slide travel of the G.M. 5" So what he does is cut them off to 4.25". This requires:
1. Cut 0.75" off the slide.
2. Recut for the bushing lug (He doesn't like bull barrels.)
3. Shorten the bushing and barrel.
4. Reset front sight.
5. Turn barrel down to .580" (less bushing relief) back to the face of the second locking lug, removing the front locking lug. He does not consider that this reduces lockup strength, and points out how little engagement there is on the usual front lug.
6. Build a skinny recoil spring guide rod and plug with small hole to take a Glock flatwire recoil spring. (He now uses the ISMI flatwire spring in a higher rating.) Clip spring to the maximum number of turns the tunnel will hold without going solid.
He was also putting Glock springs in OACPs before ISMI came out with their package deal. It works there, too. No 300 round spring life limit. I think it would be just the ticket for a Kimber Compact, too.
They shoot well. Mine came about when I took the compensator off a gun which had had the slide shortened to make a IPSC Modified "Box Gun." It worked well so he chopped his own and has done others. An update of the old pre - Combat Commander Bobcat conversion, he calls it the Polecat.
It is way more expensive than a Commander with a relibility package though. I can't say it shoots any better, either, but it is for sure different. The main difference I see is that the cut-off GM ejects its empties in the same general direction as a standard GM while most Commanders and OACPs scatter them all over.
