Another spine question

[P Carter]

I'm pretty new to the archery game, starting my third year. Typical progression: first year, just get used to shooting with hand-me-down gear. Second year, hand-me-down gear still but an interest in shooting better. Third year, new bow and starting to get serious.

The key issue for me has been shooting broadheads. Long story, but last year I was shooting significantly right. Figured out it was a torque issue that I've since corrected. This year, I've been shooting a lot with my new equipment, and I'm shooting quite well with field tips. I'm determined to start shooting broadheads early to get that nailed down for the fall. Just shot broadheads for the first time, and I'm significantly left. I haven't started tuning for broadheads yet. (No rest adjustments, etc.) Since I have to start somewhere, so I thought I'd ask about spine. I see from Easton that broadhead left can be overspined. I'd like to get folks' thoughts on spine

Here's my setup: Bear Escape 70 lbs limbs; set to 65 pounds; 29 inch draw; shooting Cabela's Stalker Extreme arrows 65/80 (.340 spine); cut to 28.25"; 125 grain broadhead (viper tricks); standard insert (20 grains); total arrow weight 440 grains (based on my calculations from components). I haven't shot through a chrono.

Thoughts on spine? I'll try to update as I attempt to tune things through.

This is all part of a longer story of trying to be successful on elk. I've had a bunch of encounters, several flat-out misses and one bad shot. If I can start shooting broadheads as well as I'm currently shooting field points I think I'll be in business.

Input appreciated!

 

[2blade]

I ran that setup thru the newest version of OT2 and it is in the good range but towards the weak side. A 100gr head hits dead center perfect but personally, I would not go any lighter on arrow weight. If you have some 100gr heads I would try it and see what that does. Quite possibly though you might get that 125 to work after some broadhead tuning. Turning the draw weight down to 62lbs puts the 125 gr head dead center as well. Is the rest centered?

 

[P Carter]

Thank you! Any idea why software typically recommends such stiffer spine than the charts? Charts put me right in the middle. Folks at the store even recommended 400.

In any case, I think i'll be able to get it to work with 125s. I agree, don't want to drop arrow weight any more. Dropping draw weight might be part of the process. My rest is probably 1/32 towards the riser from center, but I haven't tinkered with it yet. Thought I'd ask about spine first. Thanks so much, again, for your help.

 

[2blade]

You mean in the middle of the 340's? Eastons chart shows 340 or 330. Maybe the shop is over stocked on 400? I can't get a bare shaft 400 to fly straight out of a 60 lb bow at 29", has to be a 340.