Good afternoon everyone, I'm seeking your help with tuning my arrows. Here's my issue:
I have my shafts cut down as far as I can safely do and my grouping is still "nock  left".
I have 50-55 spine Douglas fir shafts tipped with 125 grain field points my bow is a 45lb longbow.
Will a heavier tip help this? Thank you all in advance.

Adam

Heavier tip may help, but it might not. Need to know a few more things to offer a more knowledgeable suggestion. It's easy to get a false reading.
How long are the arrows to back of point, and what is your draw length?
What bow are you shooting, and/or how is it cut relative to center cut?
What distance are you tuning at?
I'm assuming there's a fast-flight string of some kind on the bow.

I've been shooting woods out of at or around 45# for several years, and would be glad to try and help.

Slowbowjoe,
I'm shooting a Bear Montana with the factory string,I'm not too sure how to determine the distance of center cut? The arrows are 29.5" from the base of the field point to the center of the nock and my dl is approximately 28". Thank you for your help sir!

Slowbowjoe will give good advice. Have you shot the shafts fletched yet?

Not yet, that was my next step. I'll report back once I do!

You ought to be very close with what you've tried, I'd go with your first thought and try 145's... and also 100's if you have 'em. I find 1" longer than my draw length to be plenty, including with broadheads, but that is certainly up to you. Just thinking you might be able to cut them down another 1/2" if necessary. By all means play with the 29.5" first.

Personally, I don't think my form is good enough to get accurate feedback bareshafting, so I go ahead and tune with fletched arrows... field points and broadheads, at 20+ yards. It's far enough so I can see the arrow's behavior once it's about half way to the target.

Adam, I assume you are right handed? If so, then nock left means the shafts are weak and adding point weight will only make them act weaker. That said, I find it hard to believe 50-55 Doug fir are weak out of a 45# Montana at 28". Sure there isn't something else going on?

Thank you all for the replies, I've glued up a set of feathers and will try them out tomorrow once dry. Thanks again! You guys are a great help to a lost newbie!

Have you played with brace height? A brace height that's a little low can make them nock left.

So this morning I shot with the feathers on and the arrow flew rather well and impacted the target on a straight line. No nock left or right. I'll fletch up the rest and report back. And again, thank you all for your time/knowledge.

Adam

I like a little heavy spine arrow myself it help when I make a bad release try 135 or 145 gr points. 

https://www.youtube.com/watch?v=BSJ6-HjPMTM

That video is the best and most efficient way to tune imo. Remember, don't worry about nock orientation, it's all about point of impact.

you guys are great. Ive ordered a field point test kit to try some different weights too. Thanks again for such a great site!

Adam

Ken Beck's technique for tuning is great, but one area where I do things a bit differently is setting the nocking point. When I bare shaft tune, I work on the nocking point sooner, because I find that if the nocking point is high, the shaft that flies straight will be weak when the nocking  point is lowered to the proper spot. Stated another way, a shaft that shows slightly stiff when the nocking point is high, will be just right when the nocking point is lowered to where the shaft shoots flat. This is because the alignment of the arrow with the direction of thrust at the right nocking point is better, so the arrow absorbs more of the bow's energy.