DTAC 115 with HBN Coating Education

[YerrowSniper]

Alright guys, gonna need some education on this.
New to the PRS game and I am currently shooting 6GT.

My current load consist of 109 bergers, Varget, CCI 450 and some alpha brass.

With the whole crisis on components, I got the opportunity to pick up 1000 115 DTAC HBN coated.

What are the effects of the HBN on my barrel? What does the HNB do?
With barrel also hard to get I don’t really want to take a chance on my current gear.

Thanks!

 

[mick243]

The hbn coating will make almost no difference

it may reduce peak pressure a little

it may effect velocity a tiny bit

it might make the projo’s leave a little less copper behind

 

[YerrowSniper]

The hbn coating will make almost no difference

it may reduce peak pressure a little

it may effect velocity a tiny bit

it might make the projo’s leave a little less copper behind

So no impact on the barrel lands and grooves?
So it’s totally different then shooting moly bullet?
Should I consider the DTAC to be normal 115s with some benefits?

Thanks!

 

[Supersubes]

Tubb’s claim is less friction than moly, and no cold bore deviations.

 

[YerrowSniper]

Tubb’s claim is less friction than moly, and no cold bore deviations.

Ok, so what happens when I run out of them and go back to “regulars” do I need to handle the barrel differently before shooting my usuals?

 

[Supersubes]

He doesnt give any special instructions for shooting it that ive seen, so it would seem that you could just move on. Let us know how it goes.

 

[PatrickChewing]

I have a Tubb ATR that I shoot coated and non coated DTACs in. I asked Mr. Tubb about switching between coated and non coated. He suggested just a thorough barrel cleaning.

 

[mick243]

Ok, so what happens when I run out of them and go back to “regulars” do I need to handle the barrel differently before shooting my usuals?

the load for a coated bullet will likely be ever so slightly different (tiny bit more powder IME) than for a non coated bullet to get the same performance.

its counter intuitive, but often a coated bullet needs a touch more powder to get the same velocity - you'd think a lubed bullet would be easier to push down the bore faster, but it seems like it being easier to push drops the pressure in the chamber which alters the powder burn.

in my 243, to get the same velocity out of a moly'd bullet requires about half grain more 2208 (varget) compared to an uncoated one. in my 223 the difference is about .3gn

I wouldnt treat the bore any differently, clean it on your usual routine. when you run out of bullets drop your load 1-2% and work up again because pressure velocity will likely be off a touch (but the same applies to a new batch of powder, brass, primers too)


as for your other questions, no no real effect on the bore/lands/grooves. barrel might last a tiny bit longer (due to slightly lower chamber pressure/temperature, not because of less bullet wear...) some people say moly is a lot harder to clean - I've never had any issues with it - left in the bore there is the possibility that moly can turn corrosive whereas hbn should not, but if you're looking for an excuse to not clean then moly/hbn/bare isnt it.

 

[PatrickChewing]

Very good info in the above post!

 

[Cascade Hemi]

hBn is a friction modifier and lowers peak pressure. You will notice a velocity drop and will have to bump up your charge weight. When I've used it in the past I had to add a hald grain for 243Win and H4831.

 

[Rookie]

I shoot the coated ones and had to increase charge of H1000 by 0.4 grains. If you're concerned I will buy them from you.

 

[Baddog 0302]

I shoot the coated ones and had to increase charge of H1000 by 0.4 grains. If you're concerned I will buy them from you.

To the OP's question, if you are concerned about switching back to non coated bullets, throw a few of coated bullets in your vibratory case cleaner . That's what I did with a batch that didn't turn out the way I wanted.
I have 4 factory barrels, and use HbN coated bullets to make cleaning a lot easier.
I'm about to load some 169 SMK's and will increase the charge by .5 gn.

 

[MilSpecOkie]

I have shot several thousand HBN coated DTACS (as well as uncoated) and a couple thousand SMKs and RDFs that I coated. All in 6 and 6.5 Creedmoor.

After about 25-30 rounds your barrel will be sufficiently coated. I have had to use .3-.5 more grains of powder to reach the same speeds as uncoated bullets. Slipperier bullets won't produce the same amount of pressure so you need to up the powder charge. There is a point of diminishing returns, but you can run a bit more speed before hitting pressure with coated bullets.

I find that HBN coated bullets do not copper the barrel near as much. I use hand lapped barrels so they don't copper up much, but the bore scope doesn't lie, HBN coated bullets leave less copper in the barrel. I believe that if a person was shooting a factory mass produced barrel like a Savage or Remington that there could be a lot more advantage to running coated bullets as those aren't hand lapped and will copper much more.

I don't know what free bore you have but the DTAC may not be a good fit if you have a .120" FB like me. The DTAC is long and has a long bearing surface so you may be deep in the case or right up against the lands. Neither is ideal.

 

[acudaowner]

you have to clean and dry the bullets before tumbling them with the hbn powder or for less money and hastle you just buy the tubb per coated bullets load them and shoot them through a really good cleaned barrel and be done with it I have the hbn in a tub as well as the tubb bullets i ran the tub bullets did I see any noticable differance no improvement no was it a wast of money probably but you never know till your try it for your self . and I am a glutton for punishment if nothing else so I tried it still waiting to see if it helps this barrel last longer than my first barrel but that will take years to measure and i am not running 200 rounds per two range trips anymore so it should take even longer to reach my goal of 7500 rounds other wise it just proves to me that it did not extend the life of my barrel .