What's the case length and case volume for this cartridge? Hard to believe a 115 can go 3300fps in a modified 6mm case. Seems a little fishy...
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6mm ai too long for savage short action?
- Thread starter tbrice23
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What's the case length and case volume for this cartridge? Hard to believe a 115 can go 3300fps in a modified 6mm case. Seems a little fishy...
lloydsmale
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6mm/284
Capt RB
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It's a fireformed 6mm rem case unless you want to turn necks. If you wanted to run RWS or Norma 7x57 or 257 roberts brass. PTG would have a print. It runs right along side a 6-284 Finding brass is why I went 243ai. My smith has built a few crusaders all with ai mags and all shoot the 105 and 115 bullets through the mag. D-tacs don't typcally shoot their best above about 3150. Bergers and the JLK would tune above that though. The other thing was that GAP was shooting it in an 8 tw. I think it was a gain twist, but you'd have to confirm that for yourself. The biggest gain is in using H1000. and it is barrel life not the extra speed. At 3150 it is just cruising. If you wanted to shoot it in a single shot you could most likely use RL33 and see some terrific velocities. Getting them to shoot at those speeds has been the issue not the speed itself.
Engineering101
Well-Known Member
tbrice23
I kept the barrel nut. As I recall I changed out the barrel, the bolt head and the firing pin assembly (since the bolt head is longer, the firing pin needs to be longer and though they are adjustable for length they won't really adjust enough). Savage will sell direct to you whatever parts you want as long as you send them a letter indicating that you will not hold them liable when you blow yourself up.
I also have a 300 RUM built on a Savage Model 114 that was a 270 Win with a small shank. On that one I went to a competition lug (thicker) in addition to the other changes and of course all got bedding jobs. The 300 RUM is a .25 MOA rifle for 15 shots with the 210 Bergers - and then it needs to be cleaned or it opens up to pieplate size. It is just a cheap stainless factory barrel that I got off Numrich's website for $95 so I didn't expect much. Turns out I really like the 300 RUM so I may go for a good barrel at some point.
I kept the barrel nut. As I recall I changed out the barrel, the bolt head and the firing pin assembly (since the bolt head is longer, the firing pin needs to be longer and though they are adjustable for length they won't really adjust enough). Savage will sell direct to you whatever parts you want as long as you send them a letter indicating that you will not hold them liable when you blow yourself up.
I also have a 300 RUM built on a Savage Model 114 that was a 270 Win with a small shank. On that one I went to a competition lug (thicker) in addition to the other changes and of course all got bedding jobs. The 300 RUM is a .25 MOA rifle for 15 shots with the 210 Bergers - and then it needs to be cleaned or it opens up to pieplate size. It is just a cheap stainless factory barrel that I got off Numrich's website for $95 so I didn't expect much. Turns out I really like the 300 RUM so I may go for a good barrel at some point.
I've been running a 6CM (Competition Match) since '07. 27", 28", and 30" barrels I've had. My 30"Shoots a 115 DTAC at 3275 fps. This is one of my BR rifles. For score at 800 yards on a 600yard IBS target I shot a 99-4x 10 shot group that measured 2". My 27" Tac rifle runs the DTAC at 3153 fps. With a little more then 3900 rounds down the 27" Krieger barrel my 5 shot group at 600 yards was .4 moa. Drop tube and H1000 powder... Joe Hendricks designed this case for xtc shooting with great accuracy and extended barrel life in mind and he has achieved both.
Trickymissfit
Well-Known Member
the 6mmAI will have twice the barrel life of the .243AI right off the bat. The 6mm case length will cycle thru the short action Savage in the single shot form. I can't say anything about the magazine length for sure, but Remington has chambered the 6mm in their short action, The Remington short action in shorter than the Savage, so I think it cold be made to work. If it were me, I'd build a fast twist 6mm Vias, or a 6mmx55 improved. You'll gain about .060" in length, and that maybe all you need for the long bullets. I personally like the 6SLR, and it will easily fit the short actions.
Been shooting the 6mm/250AI for several years now, and it will max out at 3100fps using 105AMAX and 107 grain Sierras. Very comfortable at 3000fps. Neck is a little too short (like the .243), and because of this the barrel life suffers. To do this over again, I would have done it with a 6mmAI reamed short. Yet formed everything off a .243 case (sort of like the 6SLR). Remember you don't have to ream a chamber to a certain length, as you can go short or even a little long.
gary
Been shooting the 6mm/250AI for several years now, and it will max out at 3100fps using 105AMAX and 107 grain Sierras. Very comfortable at 3000fps. Neck is a little too short (like the .243), and because of this the barrel life suffers. To do this over again, I would have done it with a 6mmAI reamed short. Yet formed everything off a .243 case (sort of like the 6SLR). Remember you don't have to ream a chamber to a certain length, as you can go short or even a little long.
gary
Good advice on reaming short. My main attraction to 6mm AI is the neck length. Correct me if im wrong but According to the reamer prints I've seen if i reamed short .1" I'd be at the 243AI body length with the long neck of the 6mmAI. But there goes my velocity gain.
Thank you. That doesn't leave much room for error but that is the magic number.
Years ago I was a 6mm Rem fan. I owned several of them. I even had a 700 C grade made by the custom shop. I got rid of all of them because of the issue being discussed. They are too long to work in a short action and to use them in a long action would be wasting a long action. I suggest building a wildcat on some version of the 06 case and use a long action. I built one on a 280 case. It has the exact shoulder angle and neck length as a 6mm Remington. I don't have to fire form my brass, I can use any bullet I want and it will easily perform with a 6mm AI.
I think I still have some 6mm Rem blood in me. Every time I see something about those Defiance XM actions and their 3.2" magazines, I think about building another one.
I think I still have some 6mm Rem blood in me. Every time I see something about those Defiance XM actions and their 3.2" magazines, I think about building another one.
This has been an interesting discussion. There are so many 6mm variants and so little time to try them all.
TBRice23:
You could just use the chambering with the bullet seated deeper than the preferred base to shoulder junction. I wanted my 6mm-284 to be a repeater in a SA model 700. I put in a Wyatt's mag box which helped some but not enough. I seated the 105 berger hybrids to fit and feed and the heck with the bullet anywhere close to rifling. The rifle shoots very accurately with a significant jump to lands. Using RL-33 in the 1 in 7.5 twist 28" 5R Bartlein barrel yields 3425 fps.
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Speaking of sending in a reamer short or long......I will soon own a 6 BR. While I will certainly make this chambering I have another one in mind. I will plunge it deeper to headspace as a 243. I did this with a 30 BR reamer and am delighted with the 30 BR/308's performance. I wish I could claim the idea for the 6BR/243 but the gentlemen mentioned in the article below thought of it first. The description is grafting a 6 BR front to a 243 base. I copied this from an article:
"Gunsmith Mike Sosenko and long-time AccurateShooter Forum member John Adams have been using a modified .243 Winchester case with great success in Varmint Silhouette matches at the Pala Range in Southern California. Officially called the ".243 BR-K" (and informally dubbed the "6BR Long"), the wildcat is basically a
.243 Winchester with less body taper and a 30-degree shoulder.
The design essentially grafts a 6mmBR Norma "top end" to the .243 Winchester case. After fire-forming, Mike and John can reload this case using normal, unmodified 6BR neck-sizing and seater dies.
Compared to a .243 Winchester, the .243 BR-K's body length is about .006″ longer, and the shoulder is about .0055″ wider. The main difference is the shoulder angle (30° vs. 20°), and the location of the neck-shoulder junction ("NSJ"). Based on reamer prints, the base to NSJ dimension is 1.718″ on the 6BR Long, compared to 1.804″ for the .243 Winchester. Neck length is a bit shorter because "the neck shrinks a little when the shoulder blows out" according to Sosenko. We've provided a mock-up diagram of the .243 BR-K, but you should check with Dave Kiff of Pacific Tool & Gauge for exact dimensions. Dave created the reamers for both the 6mm and 22-caliber versions of this wildcat. Ask for the "22 BR-K" or ".243 BR-K" reamer designs."
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The advantage of both the 30BR/308 and the 6BR/243 is that no custom dies are needed. Just use the BR dies. Both chamberings will require neck turning. I setup the 30 BR for a fitted neck so I don't size the brass after firing. Might do the same with the 6BR/243. For anyone not familiar with this read what Virgil did in the story: "Secrets of the Houston Warehouse" Secrets of the Houston Warehouse
Just love LRH and the stuff we can learn or share here.
Ross
TBRice23:
You could just use the chambering with the bullet seated deeper than the preferred base to shoulder junction. I wanted my 6mm-284 to be a repeater in a SA model 700. I put in a Wyatt's mag box which helped some but not enough. I seated the 105 berger hybrids to fit and feed and the heck with the bullet anywhere close to rifling. The rifle shoots very accurately with a significant jump to lands. Using RL-33 in the 1 in 7.5 twist 28" 5R Bartlein barrel yields 3425 fps.
----------------------
Speaking of sending in a reamer short or long......I will soon own a 6 BR. While I will certainly make this chambering I have another one in mind. I will plunge it deeper to headspace as a 243. I did this with a 30 BR reamer and am delighted with the 30 BR/308's performance. I wish I could claim the idea for the 6BR/243 but the gentlemen mentioned in the article below thought of it first. The description is grafting a 6 BR front to a 243 base. I copied this from an article:
"Gunsmith Mike Sosenko and long-time AccurateShooter Forum member John Adams have been using a modified .243 Winchester case with great success in Varmint Silhouette matches at the Pala Range in Southern California. Officially called the ".243 BR-K" (and informally dubbed the "6BR Long"), the wildcat is basically a
.243 Winchester with less body taper and a 30-degree shoulder.
The design essentially grafts a 6mmBR Norma "top end" to the .243 Winchester case. After fire-forming, Mike and John can reload this case using normal, unmodified 6BR neck-sizing and seater dies.
Compared to a .243 Winchester, the .243 BR-K's body length is about .006″ longer, and the shoulder is about .0055″ wider. The main difference is the shoulder angle (30° vs. 20°), and the location of the neck-shoulder junction ("NSJ"). Based on reamer prints, the base to NSJ dimension is 1.718″ on the 6BR Long, compared to 1.804″ for the .243 Winchester. Neck length is a bit shorter because "the neck shrinks a little when the shoulder blows out" according to Sosenko. We've provided a mock-up diagram of the .243 BR-K, but you should check with Dave Kiff of Pacific Tool & Gauge for exact dimensions. Dave created the reamers for both the 6mm and 22-caliber versions of this wildcat. Ask for the "22 BR-K" or ".243 BR-K" reamer designs."
--------
The advantage of both the 30BR/308 and the 6BR/243 is that no custom dies are needed. Just use the BR dies. Both chamberings will require neck turning. I setup the 30 BR for a fitted neck so I don't size the brass after firing. Might do the same with the 6BR/243. For anyone not familiar with this read what Virgil did in the story: "Secrets of the Houston Warehouse" Secrets of the Houston Warehouse
Just love LRH and the stuff we can learn or share here.
Ross
Engineering101
Well-Known Member
tbrice23
My 7mm WSM load with 180 Bergers has a COAL of 2.970" which is almost touching the lands (less than 0.010" off). This fits in the standard Savage short action box mag - barely. The 162 AMAXs are about the same. Maybe Savage knew what they were doing or maybe it was luck.
My 7mm WSM load with 180 Bergers has a COAL of 2.970" which is almost touching the lands (less than 0.010" off). This fits in the standard Savage short action box mag - barely. The 162 AMAXs are about the same. Maybe Savage knew what they were doing or maybe it was luck.
The more i think about it the more I believe I'm going to go with 6.5mm 300wsm. I'll have to round up some 270wsm brass though. The BC for 7mm is slightly better but i have two 7mags. The 6.5mm BC is much better than 6mm.
Originally I was just looking for an easy build for a M10 action. But I might as well build something with more down range energy. I was impressed with the terminal performance of the 6.5mm140gr VLDs in my 6.5 284 this last deer season. And a short mag would fit all my needs and it is good to know I'm won't be committing a sin by chambering a WSM in a small shank barrel.
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