Stopping HBN

[Keith Glasscock]

I have been shooting my 284 a lot this year trying to develop a consistent load. Initially, I started with HBN coated bullets, and I've come to the realization that switching to H4350 makes HBN unnecessary.

At the same time, I have some issues with consistency of the loads. I've chased a lot of things around, and I'm thinking that my HBN coating process is not completely consistent.

Here is my plan - I have cleaned the barrel thoroughly and pre-treated with HBN. I'm going to fire the left-over ammunition from my last match and chrono it. Then I'll clean again (at the range) and fire naked bullet ammo to determine the differential in velocity. From there, I'll work the powder charge toward the old velocity until I find the node again.

So, my question is this: has anyone else done this? What were your findings?

Thanks,
Keith

 

[stool]

yeah ..if you are crushing necks seating bullets...you need to improve/correct your process.......
maybe start with brass prep......neck tension....

I have found hbn to work as advertised with regard to reducing fouling and am starting to accept a benefit in consistency of the impact point between cold bore and subsequent shots. However I have found that load development requires more effort than simply making a slight increase to the amount of powder. I have had to go back to the beginning and work up each load from scratch. In almost every case I have settled on a much lighter load than I was using with naked bullets with a corresponding reduction in velocity, but the loads I have settled on are easy on the brass. I have noticed one odd thing with regard to seating force after coating. The bullet on the right in attached picture shows what happens when I try to put a hbn coated lapua 123 gr scenar into a brand new lapua 6.5 grendel case. The seating force is enough to collapse the neck. The bullet on the left was tumbled in clean walnut media for 10 minutes after coating and requires much less insertion force. The walnut media removes all excess powder from the bullet and leaves a shine similar to a freshly waxed automobile. The photo doesn't really do it justice. Anyone else seen this?

 

[Keith Glasscock]

rwh's post got deleted. Read the quote and you'll know what Mike is speaking to.

 

[Keith Glasscock]

No problem.. Sometimes down the rabbit hole is where we need to go.

 

[racesnake]

I had the same seating problem with my hBN coated 308s - with a twist. After annealing, bullets were difficult to seat in Winchester brass but not in Lapua. The 308 chamber was tight neck so all neck thicknesses were the same. After cases were once fired after annealing the problem went away. To eliminate the hard seating I stopped using the Winchester brass. Never figured this one out!