Best 240 to convert from 700 BDL originally 30-06

[Trickymissfit]

Hi Trickymissfit

I am a little confused. What is the difference between the 6BR and 6BG - not finding much information on this particular cartridge.

Thanks

Robert

do this, look at a 6BR case, now stretch the area between the base and the shoulder to 1.352" from 1.078". Everything else is very similar with exception of the neck length (.330" verses .270" for the 6BR). The case is built off a standard .243 Winchester case, and is very easy to form with the proper die. When you set the headspace you simply do it with a standard .300 Savage "GO" gauge. Personally, I'd rather had a 35 degree shoulder angle, but then the gauge wouldn't work at all. Plus it's much easier push the shoulder back at 30 degrees than 35 or 40 degrees.

Here's the way I'm looking at it:

* the neck is a key factor here. It's pretty much similar to a 6mm Remington in length, which means it's going to handle those big long bullets better than the shoter neck. Add to this the known fact that longer necks mean longer barrel life in high pressure cartridges.

* the thirty degree shoulder angle will still seat well, and with the .330" neck length, you should see a 3,000 shot barrel life. The vortex of the flame path is well inside the neck, but as I said a 35 would have been even better. The 30 degree neck will also be a little less prone to the dreaded doughnut where the neck and shoulder meet, but I still think it will form much later.

* the body of the case is similar to the 6BR but as I said .27" longer. Yet we also know that the 6BR is absolutely one of the best rounds ever developed. It get's more velocity out of one grain of powder than any other 24 caliber round (a credit to Mike Walker by the way). Number two would probably be a toss up between the 6BG and the 6PPC, with the BG probably number three. The next one would be the HLS. The HLS is virtually as fast as a .243 Win. but uses less powder; thus meaning better barrel life and probably better accuracey.

* The over all length was kept at 2.04", but you can also figure after fire forming you end up with a 2.020" length (they all shrink a bit). This also means that you can use generic .243 Winchester cases (they're everywhere) to form your brass. You already have the bore size, and the hard part is pushing the shoulder back .208".

shooting the Sierra 107 grain bullet, the 6Br has been known to hit the magic 3000 fps mark, but I'd expect the chamber pressure was also way up there. Most folks are getting around 2750 to 2800fps, and that's very respectable in my book. The .243 using Magpro is rated at 3100fps, but most other powder are in the mid 2900fps area, and also using a lot more powder to get there. The 6 HLS is goof for about 2750 to 2800fps with the same bullet, but uses less powder than the .243, and is more accurate. The 6BG will push the 107 bullet to 2990 fps. My 6/250AI will push a 105 grain AMAX (dosn't seem to like the Sierra) at just under 3100 fps using H1000, or Retumbo. The loads are somewhat stiff with the 6/250AI by the way. The 6BG is probably good for about 3075 fps. I also suspect this case would be a killer necked down to .224 or necked up to 6.5
gary

 

[merbeau]

Ok, that certainly cleared up the differences between the two cartridges and does coincide with several articles that also supported the throat length issue.

There are two gunsmiths that I am thinkg of having the work done by. One is within 20 miles of where I live and the other is about 240 miles. The closer one builds mainly custom hunting rifles and has a very nice shop. I do not think he has built many wildcat type rifles. The other specializes in custom rifles and has experience with wildcat cartridges and I believe was a 1000 yard competitor at one point in the past.

I asked the local gunsmith about the LA 700 and converting to the SA 6MM BG and he said the rails in the 700 action will not allow a short bearing surface such as the 6mm BG to stay on angle long enougth to get the nose of the bullet into the chamber. They will jump out of the magazine or nose up into the top locking lug. In order to make it work a lot of metal would need to be removed or welding the inside rails which would necessarily destroy the action.

Does this seem reasonable?

 

[rscott5028]

Ok, that certainly cleared up the differences between the two cartridges and does coincide with several articles that also supported the throat length issue.

There are two gunsmiths that I am thinkg of having the work done by. One is within 20 miles of where I live and the other is about 240 miles. The closer one builds mainly custom hunting rifles and has a very nice shop. I do not think he has built many wildcat type rifles. The other specializes in custom rifles and has experience with wildcat cartridges and I believe was a 1000 yard competitor at one point in the past.

I asked the local gunsmith about the LA 700 and converting to the SA 6MM BG and he said the rails in the 700 action will not allow a short bearing surface such as the 6mm BG to stay on angle long enougth to get the nose of the bullet into the chamber. They will jump out of the magazine or nose up into the top locking lug. In order to make it work a lot of metal would need to be removed or welding the inside rails which would necessarily destroy the action.

Does this seem reasonable?

There are plenty of threads and articles about making the 6BR feed nicely as a repeater (no welding required). If the 6BR can feed, then the 6BG should be able to as well.

Practical Tactical Belgian 6BR within AccurateShooter.com

Converting Rem 700 Magazine for 6mm BR

Hope this helps,
Richard

 

[merbeau]

Richard thanks for replying. I read both of these articles and it would appear both shooters were starting with a 700 Rem Short Action whereas my Rem 700 is a Long Action. I am not sure if just modifying the magazine would be all
that would be required.

 

[rscott5028]

The principle is the same.

But, you can make the feeding issue easy on yourself if you go with anything formed off of the '06 case.

Or, sell/trade your long action for a short action.

-- richard

 

[Trickymissfit]

The principle is the same.

But, you can make the feeding issue easy on yourself if you go with anything formed off of the '06 case.

Or, sell/trade your long action for a short action.

-- richard

The Remington is a simple push feed action, and in most cases does feed very well. About the only thing I ever saw them have issues with is rounds built off the .284 case, and even that's fixable. Doing a 6BR or a 6BG probably will need a spacer installed in the magazine well. But can be made to work. Look at all the Savage 112 actions built in 22-250 and .223. That action is even longer than the Remington. Myself I use a Davidson feed ramp that sets ontop my mag well, and simply shoot the Remington as a single shot. My 6BR is on a Mod. 70 action and also uses a ramp. But can see the issue if you short pull the bolt.

If you are concerned about this issue, then I'd be looking at the 6mm Remington AI. What you could do is to ream the chamber to the same headspace as a .243AI, and have the superior neck. Or maybe ream the chamber to the same headspace as the .250AI (22-250AI will be the same). Without setting down and making a case drawing, I'd guess the neck length will be over .312" in length. Yet you should be able to use .243 brass to form cases. I shoot that round, but with the shorter neck, and it's everything it purported to be. But it's about as nice on barrels as a .243 is (maybe a 150 rounds better tops). The nice thing about the 6mmAI is that reamers are easy to come by, and all Ackley rounds are designed on the .010" taper per inch. I happen to like the 6BG because it's well known to work. But the 6/250AI is also one that shoots well. But a longer neck would make it a killer.

I've owned a couple 6mmAI's and several 6mm Remingtons in the past. Really not a lot of difference between them and the .243 till you get into the big long bullets. I think the 6mm Remington is a little bit pickier about powder selections than the .243. But as many will tell you a 6mm Remington barrel will last quite a bit longer if taken care of. A 6mm AI will last even longer due to the 40 degree shoulder. A 6mm AI will push a 107 grain Sierra to about 3200 fps on a good day, and with a very old lot of .257 brass, it can add about 75 fps. I know these velocities to be correct because I ran them thru my chronograph more than a few times. The 6mm AI is a legitiment 750 yard round with the right bullets. (I've done 670 yards without too much trouble). But still prefer to shoot it under 500 yards in my old age. I can see little if any difference between the .243 AI and the 6mm AI in recoil and initial accuracey, but things start to change when you reach the five or six hundred round mark. Neither round will be fun to shoot over a dog town, and will actually get old fast. This is where the little 6BR shines!

I'd trade the action for a single shot Mod. 12 Savage action (it will handle the 6mm AI, but will be a little tight). And build whatever suites your needs and wants
gary

 

[rscott5028]

All cartridges have pro's and con's. And, you can drive yourself crazy worrying about all of the minutia and lose sight of what's important to you.

Nonetheless, there are lots of good 6mm's to choose from.

I'd suggest picking your cartridge based on your expectations and ask your smith if he can build an accurate/reliable shooter that he'll stand behind. (or, find another smith)

If I had funds for yet another 6mm project, I'd go with 6x47L because it's sexy or 240Wby because I had a Mark V that never really performed like it should've and I'd like to see what it could do as a custom.

Since it's a hobby for many of us and most cartridges can be accurate and deadly, personal preference is a valid reason to make your choice. ...unless you're a serious competitor, law enforcement, or millitary in which case, objectivity is a must.

-- richard

 

[rscott5028]

Incidentally, I would not limit myself to a local smith unless I had high confidence in their work.

Shipping a rifle is not that costly or difficult. And, there are excellent smiths that frequent this forum whose work is respected and reviewed here regularly. These guys understand LRH and it shows.

-- richard

 

[merbeau]

Richard, you make some very good points. Sometimes there is so much information that it does make things extremely confusing. Most everyone has their favorites and I can honestly say I am no exception, however, many times (for example, the comment about the 6mm Remington) there really are valid points. I sat down last night and spent a considerable amount of time doing literature searches and reading at length, then analyzing the data and compared it to my needs. I also sat down with reloading manuals and searched sites for available components. Based on those analyses it would appear that the 6mm Remington (Ackley included), the 6mm BH and the 6mm Super LR all seem to match up to what I am looking for both in accuracy and reloading. Obviously the 6mm Remington would work well with my Rem 700 long action while the 6mm BH and 6mm Super LR are based on short actions. I started looking at several gun sales stores in the area looking for a short action rifle with good wood (like I have in the long action) that was not to expensive or could trade one of my SW 745s for.