5 land versus the 3 land polygonal rifling??

sharkathmi

sharkathmi

New member
Greetings All,
I have been itching to get a 6x45 upper for a while now.
I regret not buying one from a PM member when he had it for sale.
I've been doing a little research on my options and have a question about the rifling.
A while back New Frontier Armory did a group buy here on PM.
When they did, they offered the 6x45 in either a 5 land or a 3 land poly rifling with the barrels supplied by Black Hole Weaponry [This is my understanding. Correct me if I am wrong].
IIRC, I seen both the 5 & 3 offered on their [BHW] web site.
There is still one reference to it on their home page: Here you can see the difference between classic Enfield rifling compared to the 5 land and 3 land polygonal rifling.
Although the picture just shows the Enfield and the 3 land profiles.
I am told Black Hole Weaponry does not offer the 5 land poly rifling.
It may be possible that NFA got the 5 land barrels from someone other than BHW.

So....other than 2 lands....what is the significant difference between the two?
I'm going to assume that the 3 land is superior to the 5 land and that is why BHW does not offer the 5 land barrel.
Anyone have the 3 land? Are there any pro's or con's with that configuration?
Has anyone had undesirable results with the 3 land?
How is the accuracy?

I'm asking because if I'm going to fork over the $$ for one, I'd like to do proper research so I am satisfied with my purchase and have no surprises.

Thanks in advance for any comments you may have.

Mark
 
i wish i could help you more, i have a couple on order, (308 and 264lbc bulls) doing both builds myself, one advantage i see... since i break in all my rifle barrels, it should go a bit cleaner and quicker with 3 lands instead of 5!!! i should have them in a week or so, if you haven't made a purchase i will try and get a accuracy, short and mid range report for ya!!!
 
Skinney, I'll look forward to a pm from you after you get your rifles up and running.

Scott, I had seen both offered on the BHW site, but now they only offer the 3P. I'm slowing gaining the info I need.

Thanks for your comments guys.
Mark
 
ddw, that is what I am understanding from them.
Here is what I got in an email:
Hi Mark,
Yes, we used to offer both the P5 and the P3 with additional pricing for the P3 because it is the best.
About a year ago we decided to only offer the best, therefore we would make a P5 only upon request and as a custom request.

The P3 rifling provides superb accuracy, increasing the velocity. Our customers are constantly
sending us back a message with their happiness of receiving such a barrel with so great accuracy.

(Signature removed)

Looks like I could still get it though if I wanted to go that route.
 
Mark, I have a P3 and a P5 in the 6x45. Truthfully I can't tell the difference when im shooting them. They both are very accurate.
 
just a thought... but... say your 3 groove has less contact on the bullet your shooting, but considering it still will stabilize your round as well as a 5 groove, (maybe) since there is less contact, there is less drag on your round, "possible" for a minor increase in velocity... just a thought.
 
Originally Posted By: skinneyjust a thought... but... say your 3 groove has less contact on the bullet your shooting, but considering it still will stabilize your round as well as a 5 groove, (maybe) since there is less contact, there is less drag on your round, "possible" for a minor increase in velocity... just a thought. But with less lands, will there be....could there be a tendency for the barrel to wear faster?
confused.gif
 
Originally Posted By: sharkathmi But with less lands, will there be....could there be a tendency for the barrel to wear faster?
I would tend to think not since I have a 1903A3 Springfield 30-06 with a 1944 2 groove bbl that I have been shooting since the 70s and its still in perfect condition. Now I have not put thousands of rounds through it though, just may be 1200.
 
Originally Posted By: sharkathmiOriginally Posted By: skinneyjust a thought... but... say your 3 groove has less contact on the bullet your shooting, but considering it still will stabilize your round as well as a 5 groove, (maybe) since there is less contact, there is less drag on your round, "possible" for a minor increase in velocity... just a thought. But with less lands, will there be....could there be a tendency for the barrel to wear faster?
confused.gif


That is an assumption, and not necessarily a fact. The 3 lands could have significantly larger contact areas on the bullet and therefore more contact would indicate more friction/drag on the bullet.

From what I understand a barrel is shoot out when the throat of the chamber is eroded from the heat of the powder burning off metal. So even if there is less contact on the bullet it isn't likely the barrel would wear faster. Though I didn't understand how a barrel was "shot out" till I read a few articles about it.

Also, from what I understand about the basics of bullets, barrels, and velocity: if the velocity is increased it would likely be a sign of increased average preassure on the bullet which would indicate that the barrel was actually inducing more friction than the more common 5 grove barrels.

Most of this information is at least partially if not completely gleaned from this forum. I may be somewhat incorrect about it, but this is my understanding.
 
Originally Posted By: Jeepdude1987Originally Posted By: sharkathmiOriginally Posted By: skinneyjust a thought... but... say your 3 groove has less contact on the bullet your shooting, but considering it still will stabilize your round as well as a 5 groove, (maybe) since there is less contact, there is less drag on your round, "possible" for a minor increase in velocity... just a thought. But with less lands, will there be....could there be a tendency for the barrel to wear faster?
confused.gif


That is an assumption, and not necessarily a fact. The 3 lands could have significantly larger contact areas on the bullet and therefore more contact would indicate more friction/drag on the bullet.

From what I understand a barrel is shoot out when the throat of the chamber is eroded from the heat of the powder burning off metal. So even if there is less contact on the bullet it isn't likely the barrel would wear faster. Though I didn't understand how a barrel was "shot out" till I read a few articles about it.

Also, from what I understand about the basics of bullets, barrels, and velocity: if the velocity is increased it would likely be a sign of increased average preassure on the bullet which would indicate that the barrel was actually inducing more friction than the more common 5 grove barrels.

Most of this information is at least partially if not completely gleaned from this forum. I may be somewhat incorrect about it, but this is my understanding.

hey all were doin here is throwing out ideas "thoughts"... i will find out real fast, if the 3 land actually provide more vel. and if they have a shorter barrel life... once i get mine in to do my own testing!!!
 
All I did was throw out what I understand as far as what might be behind they claimed improvement over standard 5 grove rifling.

I am not an expert so I could be wrong, and I wasn't really trying to knock you for your statements. Just trying to explain what might be the differences based on my knowledge.

I will be very interested to find out if it has more velocity than a 5-grove. So I hope you are re-barreling a rifle that you have solid velocity numbers on, and hopefully more rounds of ammo from the same load batch as what you chrony'd before.
 
I have a three groove 16" and a 5 groove 18" and their isn't much difference in speed between the two using the same load... In theory the 16" should be 60 fps down from the 18" but its not been found to be that much spread. As far as accuracy goes they both shoot about the same size groups with the same load from a Lead Sled...
 
That is about what I kind of expected as far as velocity goes.

As for accuracy I wouldn't expect much of a change with what I understand the differences in the rifling to be. But, maybe the 3 grove could go longer between cleanings with out copper fouling degrading accuracy? That is wild speculation though.
 
Originally Posted By: Jeepdude1987All I did was throw out what I understand as far as what might be behind they claimed improvement over standard 5 grove rifling.

I am not an expert so I could be wrong, and I wasn't really trying to knock you for your statements. Just trying to explain what might be the differences based on my knowledge.

completely understand, the more ideas, info and opinions... the better IMHO, that way when i do my own testing, i have more options to take into consideration!!!
 


Write your reply...
Back
Top