Stiffer is fine, weak is bad. Sure the bow will tune up alright

 

My uncle is about the same age set his new Hoyt compound something or other just like his recurves. 45lbs 340 spine big ass heavy broadhead up front flys like a dart

 

Tip weight with soften the spine. Using a 340 at that draw weight will allow you to shoot a heavier broadhead. My soon to be son in law is shooting a 340 spine arrow with blazer vanes and a 150 grain two blade Magnus Stinger with a 46 pound draw weight. Getting great arrow flight.

 

I personally would do a 400. But he already has the 340 so try them before investing in new arrows.

 

Before you waste money on new arrows or broadheads by a field tip test kit. Field tips are cheap, arrows and broadheads are not.

 

Buy a field tip test kit. Something you will always use during your archery career.

 

plan is/was to get the bow and see how it works out. I know we're both anxious to start flinging arrows with each other again after all these years. Will keep you posted.

 

A over stiff spine can work just fine if you load the front like folks have mentioned. When I was bow hunting that is what I did every season. You can get brass inserts that make it very simple and clean to add tip weight. I have them in some hunting arrows. They hit like a sledgehammer.

 

That seems mighty stiff to me.

 

With a properly timed drop away rest, I don’t think you can get an arrow that is too stiff.

 

Just go in a shop that sells individual arrows and buy a couple of .400's. Let him shoot them against his existing arrows and see if it is more accurate. If the .400's shoot significantly better, then he can consider if he wants to get some.400. I do this all the time, shoot different spines against each other. And sometimes based on the total build..tip weight nock end weight, broad head, whatever......an over spined one will shoot better or worse. he will be significantly over spined in a .340. It helps a lot if you determine about what speed you want to shoot, and use a calculator to determine what weight arrow will put you in the velocity range and trajectory you are looking for. I bet his current arrows are probably heavier than he might like. I am thinking he probably won't want an arrow much over 375 grains or so. And the lower spine arrows are lighter in grains per inch.