I have a custom 20" barrel, Whyled chamber.  After working up loads and getting it down to around .7" I get flyers 1 - 1 1/2" out.  A change in .1 Gr throws all sorts of scatter.

A base loaded 75 Gr BTHP and a COAL of 2.264" seems to be in the ball park.  But still no consistency.  I got a Hornady chamber gage and measured the throat of the chamber.  I must admit I got a bit of a shock.  The difference between the75 Gr test round and the 75 Gr extended out to touching the lands is .172"

So if I'm reading this right the bullet free travel jump is .172" before it contacts the lands.  Is that normal for a Whyled chamber AR?

Bryan
Manassas VA



Let me state this again.

In a case loaded with a 75 Gr BTHP, and a COAL of 2.264.  That BTW is .004 oversized per SAMI specs.  The bullet is cannelure is just peaking out of the case.

Most common wisdom places the ogive .005" - .015" from the lands.  That's five thousands to fifteen thousands of an inch.  I get that.  What I'm saying is in my rifle, the bullets jumps not .005 - .015" but .172" before it engages the lands of the barrel.  It has to travel .172" before it engages the lands.  That's not five thousands, but - one hundred and seventy two thousands - of an inch to engage the lands of the barrel.

In looking at the SAMMI specs I think the dimension from the breech face to the lands should be 1.857".  Mine looks to be around 1.901"

Is this right, or did the guy that reamed the chamber really screw this up?

Bryan

The Wylde chamber throat angle is 1.5 degrees, .223 is 3 degrees. Heavy bullet 5.56mm loads used in NRA highpower rifle tournaments at the 600 yards line are loaded one at a time directly into the chamber. They will not fit or feed from a magazine.

Typical OAL is between 2.375" to 2.550" when loading heavy bullets in ,223 depending on which chamber is being used and who's bullet is being loaded.

Hornady 75 grain hpbt Match, Sierra 77 grain Match Kings and Nosler 77 grain custom competition bullets are designed to be seated between 2.250" and 2.260" and feed and function from the magazine.

Hornady 75 and 80 grain A-Max bullets, Sierra 80 grain Match Kings, Nosler 80 grain Custom Competition, Berger 80/82 grain and their match 75 grain VLD's are all meant to loaded long (+/- 2.500") and inserted directly into the chamber a single shot at a time. You have to measure jump to rifling when using any of these bullets, making sure you're not going to jam them into the rifling. Start around .020" off the lands and work forward (longer) in .010" increments.

I load Hornady 75 grain hpbt match bullets at 2.250" oal. Powder charges that work best for me have been 23.5 grains of VV N540, 23.5 to 24.0 grains of Varget, RE-15 or N140. 22.5 to 23.0 grains of H4895 can work well too. All of these powder charges are at or near published maximums. Start lower - work up.