Different arrows, same POI?

[JMSmithy]

So here goes
 
Only been shooting traditional about year now.  Practice quite a bit, shooting high tech stuff about 30 yrs...

Shooting Widow PMAII 50#@28 62" bow with 28" draw.

Here's issue, I shoot, interchangeably Beman MFX 400, Griz Alaskan and Sitkas, cut to 30-30.5" with 315gr filed points (shoot Ashby Broadheads).

My arrows all hit within same 6-10" circle, centered in my target at approx 20 yards.  Bare shafted I have them all hitting straight on.  Through trial and error I have found my best brace height to be 8 3/8"

What gives?  Makes no sense really and I know I shouldn't look gift horse in the mouth but....

Any thoughts?  I'm all ears...

Be well >>-->  

[Trad-Man]

What exactly is the question?

Out to 20 yards you can launch practically anything and keep them all in a 10" circle....500 grain arrow through a 1500 grain arrow.

[reddogge]

That isn't unusual at all. Last week I went over to my buddy's house to try his 50# limbs on his Buffalo and we shot 45-50# limbs, 2016, 1916, GT1535, GT3555. They all shot the same and printed the same spot.

[Ravenhood]

As long as my arrows are tuned, I see little differance in slight weight changes.

[JMSmithy]

Shouldvv been more specific,plus typed wrong...at 20 I'm in 3-5" circle, 35 yards in 6-10".  Just seemed strange to me that such radically different arrows would hit pretty much same place.

[Bonebuster]

I`m like everyone else. At 15 to 20 yards, any arrow combo that I have tuned to my bow will all group together.