Surprising Results M405

[SEW]

After re-equipping my M405 with various accessories, I planned on resighting it in from last year's settings. I expected to put a different tape on my Optimizer. The arrows of choice are Boo's Blazer fletched 18" Zombies, plastic nocks, 26g insert/FOCs - 397.5g. Just to see how they'd do I also tried SSAS factory fletched STs/50g insert/FOCs(430g).
As expected, the Boo prepared arrows were grouping appx 1" @ 60 yds. What wasn't expected was all the arrows (both Boo's and the factory fletched, heavier STs) had the same trajectory. Why?? Pictures are below. I'd planned on de fletching the Spynal Tapps, spine indexing them and then refletching. That plan's on hold.
The pictures below tell the story.
The M405


White fletching STs, red - Boo's. Note: the STs often have up to 2" horizontal spread ar 60-80 yds. Happened here. The aiming point was the red dots on the tgt.


Here is a 60 yd pair of shots : Boo's arrow with a 170g field tip and a ST with a welded shut FOC. This picture isn't a fluke : it happened repeatedly. It's like the M405 doesn't care which arrow is shot out of it, it's just going to hit the same place regardless.

[vixenmaster]

Lookin good jus like Robin Hood shoot on stick

[nchunterkw]

Maybe a little more drag on the helical fletched blazers than the STs evening out the trajectory between the 2 ?? Or maybe a little better energy transfer to the 430 gr arrow?

Great illustration of why you have to test every change you make. Sometimes the results aren't what you think....in this case, in a good way!

[Eck]

These crossbows are interesting creatures. Very similarly, I discovered by accident that an odd QAD Exodus broadhead I had been given was NOT a 100 grain head as I had assumed, but a 125 grain model. I had shot it with my 100 gr. Slick Tricks just to see where it hit in relation to those, and it grouped exactly the same as the Slicks at 20 and 30 yards with all 3 of my bows. With that, I figured it MUST be the same weight as the Slicks. I ordered some 125 grain Exodus heads, and when they came, I thought . . . They don't look any different that the 100 grain head I already have!!??

My powder scale solved the mystery, but I'm still amazed that the two heads fly the same out to 30 yards with a 25 grain difference in weight.

Maybe weight matching isn't time/effort/money well spent on arrows?

[bigrak]

Interesting and informative!
Love your posts!!!

[Carnivorous]

These crossbows are interesting creatures. Very similarly, I discovered by accident that an odd QAD Exodus broadhead I had been given was NOT a 100 grain head as I had assumed, but a 125 grain model. I had shot it with my 100 gr. Slick Tricks just to see where it hit in relation to those, and it grouped exactly the same as the Slicks at 20 and 30 yards with all 3 of my bows. With that, I figured it MUST be the same weight as the Slicks. I ordered some 125 grain Exodus heads, and when they came, I thought . . . They don't look any different that the 100 grain head I already have!!??

My powder scale solved the mystery, but I'm still amazed that the two heads fly the same out to 30 yards with a 25 grain difference in weight.

Maybe weight matching isn't time/effort/money well spent on arrows?

Funny you should mention this. I found the 100gr Ram cats and 125 exodus had the same poi out to 30yards as well. The 125gr Exodus seems a bit more solid than the 100gr. 125gr all the way for me..

[SEW]

This is the same 20-60 yards! We'll see to 80 or more next time the wind is nearly non-existent .

Another important point: notice the heavier and more foc'd arrows on the right of the Spyderweb tgt: they penetrated deeper. Same bow, only 32.5g difference but noticeably more penetration. I'm becoming more convinced that ft lbs of energy doesn't tell the whole story; because in this case, there is only negliable ft lbs difference but significantly greater penetration. Momentum and more foc seem to play a significant role in penetration. If momentum didn't , a 45acp wouldn't be do deadly.