Barrel contour smothe vs stepped for accuracy

[gme]

To answer the OP's question, most barrels that accept a reflex suppressor are machined with a straight section near the muzzle, you could do a taper but will still need a small straight section for the bushing to center on, I would think the harmonics of having the can making contact with both the muzzle and the barrel some distance back would be a bigger concern than the profile of the last few inches of the barrel

 

[johnmventers398]

To answer the OP's question, most barrels that accept a reflex suppressor are machined with a straight section near the muzzle, you could do a taper but will still need a small straight section for the bushing to center on, I would think the harmonics of having the can making contact with both the muzzle and the barrel some distance back would be a bigger concern than the profile of the last few inches of the barrel
View attachment 1325569

Thanks, this although there has been some really interesting reading g this is the first response that seems to fully grasp the question. That is probably entirely my fault.

As an additional note. My mod does not accept a bushing at the back so will not be supped by one.

 

[johnmventers398]

John,
Reach out to forum member Boyd Allen @BoydAllen
I believe he described to me in great detail some testing he has done along the same lines with good success.

CW

Thanks for the contact

 

[johnmventers398]

The short answer is Yes, a stepped profile rather than a gradual taper can perform well. If you look at the AR-15 barrel profile that ALL service rifle shooters use to compete in CMP and NRA highpower rifle competition, you will find the following dimensions to be used with great accuracy out of an AR-15 platform (sub MOA at 600yds).

-20” length overall
-1” dia for something like the first 16 inches.
-.750” (this is appropriate. I don’t know the exact number off hand) dia from 16” to 20”

The transition from 1” to .750” is an immediate and abrupt step. The x-ring at 600 yds is 1” MOA and guys can shoot 50%-75% of their shots in the x-ring when shooting prone with a sling. Obviously there is plenty of user error there so the platform is capable of sub MOA.

hope this helps.

I hadn't even considered AR platform barrel profiles. Probably because there not used in the uk. But yeah that is a fairly good proof of concept.

 

[Dusty Stevens]

I hadn't even considered AR platform barrel profiles. Probably because there not used in the uk. But yeah that is a fairly good proof of concept.

Not known for accuracy though.

 

[Bamban]

I hadn't even considered AR platform barrel profiles. Probably because there not used in the uk. But yeah that is a fairly good proof of concept.

2001 while on business trip/vacation to the UK I had the opportunity to shoot on a range outside London (not Bisley) everyone on the range had AR15s with courtesy devices. However, none of the of the rifles had any gas system, they were manual AR15s with side chargers, and with buffer and spring.

Maybe rules have changed by now.

 

[Old Navy]

Not known for accuracy though.

They can be be if done right. Not for bench rest for sure. Under .5 moa will be good in other disciplines.

 

[Alex Wheeler]

I have been using a contour now for a few years thats steps down and stays straight. Its done some winning for sure, maybe even an agg record or two. Better than an HV? Dont know yet. Too small of a sample size. It takes a very long time to start to see a trend in equipment. You cant base this stuff on a hand full of barrels or rifles.

 

[DaveTooley]

Just a small sample but I have used several leftover contract AR barrels on my own bolt guns. It may look a bit odd but I've never had an issue with accuracy with or without a suppressor. A good barrel is just that. Good.

 

[Bamban]

I have been using a contour now for a few years thats steps down and stays straight. Its done some winning for sure, maybe even an agg record or two. Better than an HV? Dont know yet. Too small of a sample size. It takes a very long time to start to see a trend in equipment. You cant base this stuff on a hand full of barrels or rifles.

May I ask, how long is the straight?

 

[Bamban]

Just a small sample but I have used several leftover contract AR barrels on my own bolt guns. It may look a bit odd but I've never had an issue with accuracy with or without a suppressor. A good barrel is just that. Good.

Thank you for the input, Dave. We've had similar experience. Michael Turner modified the front end of a 721 and the bolt so we screw in the AR15 barrel tenon without the barrel extension. Mark Pharr, Tumbleweeds Custom Rifle donated a bedding job on a fat stock. I had him cut the stock short enough that we can change barrels without taking the barreled receiver out. We use this rig to test the barrels for the juniors after meloniting.

As you said, "a good barrel is just that... good" The best barrels were finished and issued to our best shooters.

 

[BoydAllen]

Last year, I took a good shooting HV profile 6PPC Barrel and machined 4 equal steps in it. I was careful to take light cuts, avoid any chatter and use plenty of coolant.

As best I can tell, it shot exactly the same as before.

How much weight was removed?

 

[BoydAllen]

I've always thought the wild fluting on some of the barrels looked cool, but I stay away because I wasn't sure about this.

There is a lot of opinion here with scant experience. Back in the late 90s, I stepped the front half of a buttoned LV barrel to take off the same weight as a tuner I added. The accuracy was improved.

 

[DaveTooley]

There is a lot of opinion here with scant experience. Back in the late 90s, I stepped the front half of a buttoned LV barrel to take off the same weight as a tuner I added. The accuracy was improved.

The target tells all.

 

[joshb]

Ok. I have always wanted to build a custom gun with a hexagonal barrel. I wanted to do it on my last 6.5-55 build but several guys talked me out of it because it could “ruin the accuracy”. What would be the way to have one made, then?

 

[Dusty Stevens]

Ok. I have always wanted to build a custom gun with a hexagonal barrel. I wanted to do it on my last 6.5-55 build but several guys talked me out of it because it could “ruin the accuracy”. What would be the way to have one made, then?

Dont let folks talk you out of stuff you want to do. I did one on a tikka 595 that was exactly the same size as the action once i took the taper off the front then tapered it round past the forend. It was no worse than any fluting or anything else