Elk arrow spine question

[Healwithsteel]

Hey all,
Please help me decide if I need to buy different arrows.

I just bought a used PSE EVO EVL 34 and am getting it set up for elk. It came with 6 black eagle rampage shafts, 300 spine.

My draw length is 30.5-31, draw weight 70 lbs, IBO 338. I plan on shooting a solid COC like the cutthroat broadhead with a total arrow weight of 500-550 grains.

Will these be under spined in this set up and should I get 250 spine arrows? Thanks for your time!

 

[GatorGar247]

You will have to put a bunch of weight on the front of those arrows to get to 550. I think you would need 250s. I draw 29.25 and shoot 75 lbs 150 up front and cut my 300 spines to 27.25. Much longer or more front weight I'd need 250s

 

[5MilesBack]

It's hard to say. I've always just tuned the bow to wherever it needed to be to shoot whatever arrows I was shooting. That was easy with yokes. My draw is almost 33" and my arrows are all cut to 30" ctc. Currently shooting RIP TKO 250's at 500gr with 200gr up front. Last Dec I picked up a Mathews Traverse which is also listed at 338. Had never dealt with cam shimming or top hats before. I set the center shot to 13/16". I'm left-handed and with the 70lb limbs fully cranked down bare shafts were left of fletched. So I moved the cams to the right in two different increments, and now they are as far right as they'll go. BS's were still a little bit left but I figured I'd fine tune it all later.

Fast forward to this last week and I finally started doing some shooting. Well, I felt some pain in my right shoulder and elbow so turned the bow down a turn and a half. After some shooting I tried some BS's. At 40 yards they were now right of fletched. I also tried some 441gr RIP TKO's with only 141gr up front. Same thing.......BS's right of fletched. Tried my 520gr GT Kinetic XT 200's BS's and fletched and they too were right of fletched. Tried my TR Crush 300's and they were the same......BS's right of fletched. Four different sets of arrows with four different dynamic spines.

So I cranked the limbs all the way down and shot them all again. BS's were all left of fletched. So I started turning the limbs out 1/4 turn at a time until BS's were hitting with fletched, and were parallel with each other. At a 1/2 turn out my 500gr RIP TKO's were perfect. The other arrows were close, but would need a little more fine tuning if I was going to shoot those. So whether you need different arrows or not is up to you, but you can probably get those 300's to work if you try. Lots of ways to get a bow to make arrows do what you want them to do.

 

[fatlander]

Only way to find out for sure is to shoot them.

If you exhaust all other options, then you probably need to drop a spine. But I’m betting you’ll be able to get them to tune.


Sent from my iPhone using Tapatalk

 

[ResearchinStuff]

download the week trial of pinwheel and see what it says.

I shoot an evolve cam bow at 70#, 28.5" DL, and 300 spine arrows - my guess is no way will you get to 515 gr on a rampage with adequate spine at your specs and starting with 300 spine arrows.

 

[Tilzbow]

I shoot similar bow specs and with a .300 spine arrow I’m limited to 100 grain broadheads and standard aluminum inserts. I shoot .250 spine shafts as a result.

 

[Healwithsteel]

Thanks so much everyone for weighing in, I’m definitely gonna grab some 250 spine arrows. I just foresee a lot of fiddling and wasted time trying to get the 300 spine arrows to tune with heavy cut on contact broadheads.

 

[Bretc36]

Good thread

 

[stanginthe11s]

if it were me I would put a lighted nock, wrap and 125 gr head to get my 500 gr at 30" and then shoot the bow. theres no such thing as wasted time when tuning a bow. that arrow will work and getting it to fly perfect will only help you later if you go with a different shaft. at worse, you get to learn the new bow and not mess up arrows that you paid a lot for.

 

[LuvsFixedBlades]

Shoot a test arrow through a chrono with your new bow. Get a 3-5 arrow average for speed.

Weigh your test arrow.

Feed the data into Archer's Advantage or other shaft selection software along with your DL and DW.

You can play around with the front and back end of arrow components within the software to achieve your desired FOC and build goals. Then use it to determine how short/long to cut the shafts to achieve an optimum spine config. Maybe you need stiffer spined shafts, maybe not.

Assuming DL, DW and IBO's are correct based on factory specs alone isn't good enough. We don't know what components are on your string, if you got a hot/weak set of limbs, hot/weak string set, etc. You must shoot known weight test arrows through a chrono for best results.

If you get the required info above and share here, I'll spec out an arrow build or two to help get you started.

 

[CobraChicken]

You will have to put a bunch of weight on the front of those arrows to get to 550. I think you would need 250s. I draw 29.25 and shoot 75 lbs 150 up front and cut my 300 spines to 27.25. Much longer or more front weight I'd need 250s

Second this. Imo I'd go 250. Throw some weight up from with inserts and/or footers. I have about the same draw and my ibo is a little faster.

To get 535g axis 4mm I shot last year to even out on my omen, I had to go 250 and load up about 180g I'm the front cut the arrow down some to get close to that weight without being weak.

Pinwheel is your friend. Sure there are better apps out there, but it's worked for me