Barrel crown question - 6PPC

[potatoe]

I just picked up my barreled action from my FFL today and noticed that there is not really any crown on it that I can tell, atleast not recessed. I'm unable to reach the gunsmith this evening (the smith is very highly regarded) and wanted to post here to get input.

Granted we never spoke on the crowning, I pretty much assumed it was a package deal with a chamber job. Also I didn't just get a chamber job from the smith, there was much more work done on the barreled action. The smith is very well known for short range benchrest, and this is my first short range build so I'm not sure if a recessed crown is standard in this field or not.

 

[RDavies]

It looks like you got a flat crown. A few gunsmiths have done the same on my target rifles. I,m seeing more high end BR rifles with the same.

 

[WyleWD]

A recessed crown would be a "must" for me. Talk it over with your smith and see what he says. He is the one you'll be talking to if there is some issue, so IMHO by all means get his input on it. WD

 

[potatoe]

When I run my finger across the end of the bore it is quite sharp.

 

[SS427]

You are good to go. I understand a 90 degree flat crown is easier to make perfect. I'm not a machinest so I don't know that for sure but it makes sense to me.

I don't see a need for a recessed crown unless it is a hunting rifle and there is a chance of damaging a crown. I've yet to see a need on a benchrest rifle.

 

[artbosco]

I just picked up my barreled action from my FFL today and noticed that there is not really any crown on it that I can tell, at least not recessed. I'm unable to reach the gunsmith this evening (the smith is very highly regarded) and wanted to post here to get input.

Granted we never spoke on the crowning, I pretty much assumed it was a package deal with a chamber job. Also I didn't just get a chamber job from the smith, there was much more work done on the barreled action. The smith is very well known for short range benchrest, and this is my first short range build so I'm not sure if a recessed crown is standard in this field or not.

My smith, Billy Stevens: http://www.stevensaccuracy.com/ always recesses the crowns on my Light Varmint and Heavy Varmint barrels that are tapered Krieger's. When it's recessed it provides greater protection for the rifling. Also, the barrel in the photos looks like a Bull barrel, that's normally associated with a much heavier barrel than the Heavy Varmint. To my recollection Bull barrels are only seen locally in fun matches, vice competitive matches, due to weight restrictions. The LV being 10.5 lbs and the HV being 13.5 lbs. Personally, I've never seen a 6PPC with a Bull barrel. They look neat, but you won't see them in big registered matches.

 

[jscandale]

Potatoe,

The type of crown is not important to accuracy. Different types of crowns appeal to different folks. The thing that matters the most is the concentricity so when the bullet leaves the bore, it is released by all of the lands at the same time. Personally, I prefer either an 11° or a slight recess due to the simple fact that it offers a small bit of protection against minor bumps but flat crowns will perform just as good as any other.

JS

 

[potatoe]

Thanks for all the replies.

Outdoorsman: Thats yet another issue I have with the barrel, besides the fact it's a .262 instead of the .268 I asked for.

 

[fdshuster]

potatoe: There is a very interesting article on muzzle crowns in the February issue of "Precision Shooting". Backs up the theory that the type of crown does not matter, as long as it is symetrical.

I bought a used bench rifle with 2 fitted barrels. One had a recessed crown, the other was flat, like yours.Shot them side-by-side & could not tell any difference in group sizes.

I also prefer to have at least minimal protection from possible damage, so had the flat one recrowned with the traditional 90 degree sunken. As before, no difference in group sizes.

 

[Eddie Harren]

"Personally, I've never seen a PPC with a bull barrel......"

Obviously you have never been to a championship match where one of the four classes contested is Unlimited or Heavy Bench. Commonly called railguns. Stick around you're learning.

 

[fdshuster]

Second what DocEd said. The vast majority of barrel contours, 6ppc, 6BR's, etc. are all heavy varmint, straight taper, being used in our benchrest for score match's, distances from 100 to 500 yards & meters.

Many would easily make the 13.5# weight limits of the heavy class.

 

[lpreddick]

potatoe: am i missing something? your photos depict a barrel blank still in the mesh sleeve. second photo is the blank all by itself. as we know, the muzzel end of a blank is removed with about 1 in of barrel. what does the barrel look like in the action? i have banged the muzzel of all my guns at some point and am very thankful that my crowns are recessed.

 

[potatoe]

Somehow I managed to get the pics to hide the rest of the barreled action. The mesh was left on the barrel after chambering for shipping. The pic is of the barrel attached to the action, chambered and crowned.

I did talk to the smith this morning and it is a flat target crown, I was not aware that they did such crowns.

 

[artbosco]

"Personally, I've never seen a PPC with a bull barrel......" Obviously you have never been to a championship match where one of the four classes contested is Unlimited or Heavy Bench. Commonly called railguns. Stick around you're learning.

Ed, Most people don't consider railguns as a traditional rifle which is what I was referring to. But you're right. Railguns have Bull barrels. I've seen many but only considered them a mechanical aberration.

There were plenty of those funny looking things at the NBRSA Nationals in Midland. Even saw Wayne Campbell acting as a caddy for Tony Boyer because it weighed so much.

Never really considered them more than a testing tool because of the auto-return-to-battery mode. Probably should be called a wheelbarrowgun instead, because that's what you need to tote them around.

 

[Eddie Harren]

LOL!

 

[artbosco]

The vast majority of barrel contours, 6ppc, 6BR's, etc. are all heavy varmint, straight taper, being used in our benchrest for score match's, distances from 100 to 500 yards & meters. Many would easily make the 13.5# weight limits of the heavy class.

I placed my confidence in Billy Stevens expertise in building both my rifles for NBRSA registered competition and was extremely pleased with the results. He built my LV/Sporter 6PPC with a tapered barrel for short-range 100 to 200 yards Group matches with a provision to be able to add a March Scope later on as an option over my Leupold 45X. It was built underweight in order to do that. The same with my HV 30BR for Score. It was also was built slightly underweight.

Bull barrels don't necessarily lend themselves as a good option to a weight increasing rifle in the future and still stay within rule restrictions. I suppose it could be done, but staying with a 20-22 inch barrel would probably require some magic elsewhere to stay underweight in the present.

You won't see any Bull barrels on this line: http://www.youtube.com/watch?v=kyr_KABHBg4&feature=related or this one too: http://www.youtube.com/watch?v=kd-irq17RLg&feature=related

 

[Eddie Harren]

You win. You are right. Railguns are not rifles. Tony will have to give back all the HOF points he got with his railgun.

 

[watercam]

+1 on the Precision Shooting article - great test that everyone should read. It is the Feb. 2012 issue.

 

[BoydAllen]

The crown will shoot fine, if the machining was properly done. In the future you may have one more thing that you want to specify.

As to the PS article, a friend was telling me about it. I could have heard it wrong, but she tested to compare accuracy at 200 yd. without flags? and cut off the barrel with a parting tool. The first is obvious, for the second, wouldn't a saw cut be better?

 

[fdshuster]

Boyd: The original idea was to test if one type of crown was more accurate than another. The first tried was the 11 degree, then the 90 degree recessed, a 45 degree, and finally a really deep 90 degree. Each group fired was smaller than the previous, and the consensus ended up being that as the barrel was shortened in 1/4" increments for each crown, it was reaching the ideal "sweet spot", for that barrel & load. 308 w/ 168 SMK's.

It would have been interesting, if the test were continued, to see if the 11 degree crown ( first tested) would be smaller after the barrel had been shortened.

A very well written, informative article in P.S.