Chamfering & Accuracy

[gomeybear]

Curious if one would see an appreciable difference in 300 blackout accuracy by chamfering all cases?

Debating whether or not I should add chamfering in to my reloading process. Ive chamfered before to minimize seating pressure with flat base bullets, but never with intent to improve accuracy.

If I stand to improve a bit in accuracy, I may pick up one of the Giraud Tri Way Trimmers.

[rlandry6]

I can't imagine not chamfering any rifle case. It keeps you from shaving the bullet when seating.

[AR-300]

No need to chamfer BT bullets.
Flat base need it or shave rings appear

[dellet]

Curious if one would see an appreciable difference in 300 blackout accuracy by chamfering all cases?

Debating whether or not I should add chamfering in to my reloading process. Ive chamfered before to minimize seating pressure with flat base bullets, but never with intent to improve accuracy.

If I stand to improve a bit in accuracy, I may pick up one of the Giraud Tri Way Trimmers.

Whether or not you see a change in accuracy, will depend on your ability as a shooter and hand loader. Seating the bullet straight is the goal.

Flat edge to flat edge, is the hardest to seat.

Flat edge to taper is easier to force together, but will only be straight if both mating edges are square.

Taper to taper in theory should self align.

The goal is straight necks and loaded bullets and a chamfer will help that. The other thing it will do help even out the feel of seating a bullet, the pressure required. Then when you feel a tight/loose one, you can set it aside and potentially eliminate a flyer.

That all can help on the road to more consistent groups and accuracy.

[gomeybear]

Whether or not you see a change in accuracy, will depend on your ability as a shooter and hand loader. Seating the bullet straight is the goal.

Flat edge to flat edge, is the hardest to seat.

Flat edge to taper is easier to force together, but will only be straight if both mating edges are square.

Taper to taper in theory should self align.

The goal is straight necks and loaded bullets and a chamfer will help that. The other thing it will do help even out the feel of seating a bullet, the pressure required. Then when you feel a tight/loose one, you can set it aside and potentially eliminate a flyer.

That all can help on the road to more consistent groups and accuracy.

Appreciate the responses. This makes alot of sense. The Speer TNT 125 grain that I was reloading the other day is definitely a flat edge to edge bullet profile.

Right on Dellet..... When loading unchamfered cases with Speer TNT 125, I noticed that it was messing with my concentricity so much that some of my reloads didn't have adequate neck tension and could be pushed in by pressing the tip of the loaded bullet on concrete. At least that is my theory on it....

With flat base bullets like the Speer TNT 125 grain, could not chamfering have that much affect on concentricity that some bullets dont have adequate neck tension as a result?

[Netpackrat]

I am using a Lyman "M" die for case neck expansion and to give a very slight flare to the case mouth prior to seating the 125gr TNT, and it has worked out well for me. Without the use of the M die, even with chamfered necks, I was getting shaving of the TNT bullets.