I haven't visited here for a long time. I'm having trouble getting an arrow weight configured that I want. Shooting 57# @ 26" draw on a recurve. I'm wanting 11 to 12 gpp. The best I get with a 400 xx75 aluminum is just under 10, and with the bemans carbon just above 8 gpp. The shafts on the Easton chart list the aluminum @12 gpi for a 400 spine shaft. I don't recall the beman spine weight (obviously less). I'm using 175 grn for the aluminum with standard inserts and 125 for the carbon with 100 grain inserts. I'm trying to keep my arrow length to no greater than 29 inches. I also don't want to fork out the money for more broadheads. For 40 years I've tuned and shot but my experience with white tailed deer is that the heavier arrows work better. Now I want an 11 to 12 gpp arrow. I'm at the point of exasperation. Seems my arrows stay between 8 and 10 gpp.
Try the 100 grain inserts with 175 grain heads on aluminum . Cut arrow back until it's stiff enough. This may get you around or just under 11gpp. The higher foc will help penetration. Otherwise may have to fork out the money to get exactly what you want. Hope this helps. Good luck.
You could go up one spine level and load up the front end. That would get you there with aluminums or carbons. Does add some expense though. May not even need to change spine levels. Just try loading the front end more and see if it works. If you don't want to change points, use heavier adaptors and/or inserts.
Thank you for the responses. It got my brain out of hydraulic lock. I'm going to try the heavy inserts on the aluminums. According to the 3 rivers spine calculator, which is really close to my calculations, I should get a one gpp increase. I do want more but to get there I might have to fork out the money for broad heads. I mean, the price of them is painful.