6mm 105 and 107 velocity debate. How fast can they be pushed.

wildcat

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Jul 16, 2005
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Hey guys, I ve decided to build a 6x284, and I am going to design it around the 105 and 107grn bullets. I spoke with Krieger, and they recommended I use a 30", 1-8.5 twist, 4 groove barrel, for 105 and 107grn bullets out of the 6x284.

My question is, how fast can I push the following bullets out of the above mentioned twist rate and groove without them blowing up.

1. Berger 105grn VLD
2. Sierra 107grn Matchking

My goal is to push them around 3500fps or faster. I will be using a Nesika Model L, 1.470 Diameter action.

Wildcat
 
safely 3350, ruining brass 3550. you just need to decide whats more important. 3500 fps and buying $.84 brass after each shot or having better brass life and less speed.

we all know what road you are gonna take, just hope you dont have to turn the necks.

d-a
 
I am looking at using the Lupua 105grn Scenars, and I will be using a 1-8.5 twist 4 groove barrel. If 3500 fps will ruin the brass, then I will go for 3400fps. I just wanted to get the info from you guys who have used these bullets. Anyhow, I am hoping to get more info from everyone. Krieger, informed me the 1-8.5 twist 4 groove was working real well with 105grn bullets and the 6x284. I took their advice. I am looking forward to this rifle, and I just want to get some more info regarding how fast can the 105 and 107grn bullets be pushed without blowing up, it sounds like 3300 to 3400fps.

Wildcat
 
blowing them up. the 105 amaxes will let loose @3200 or so with a 4 grove kreiger. the 107 smk's and 105 bergers have yet to dust one. Both of those i have had to 3500 in my gun. I havent used the lapua bullets and probably wont. I need an expanding bullet for what i do.

d-a
 
d-a,
What have you had for performance on hair with the Berger's? I've killed deer with the 107 quite a ways out but they stopped working at 400 yds or so. All the A-maxs come apart so I have been experimenting with 95 gr BT but haven't got a good load. I keep coming back to the 107 and probably should stay there as I keep using up barrel on paper. I can get 3300 with the 107's and RL-22 in my 30 inch Rock but it makes Lapua primers start to get loose. It was really hard on Norma brass so I would be interested in a 3500 fps load that didn't eat brass after one shot.
Lance
 
The bergers at the speed i am shooting have been great on deer and hogs. Generally I dont get an exit under 300 yards but rarely do they go 20 yards with most drt. the 107 have worked well for me farther than 400 yards too. I shot a 140 lb doe at 575 and she drt and had a softball sized exit. I did shoot her high shoulder.

As far as loads i couldnt get the velocity i needed with Rl 22 and everyone swears by it. I found that retumbo worked for me and it is a compressed load around 103% load density by QL

the norma brass is soft i stay away from it. the 3500 fps is hard on brass i stay away from it too.

I am waiting on the new 117 dtacs to see what i can get out of them. they should do well on deer and hogs with the poly tip.

d-a
 
Thanks for the info so far. I am leaning towards using the Lapua 105grn Scenar and the Berger 105grn VLD for this project. I know I can shoot them as fast as 3600fps, however, I am going to go far the 3400fps mark. I spoke with someone at Krieger today, and they said their 1-8.5 twist 4 groove barrel is shooting the 105grn Lapua, and Berger, very well. Please, keep the info and opinions coming.

Wildcat
 
Wildcat,

Here is the bottom line. The 6-284 doesn't do anything better than a 243 imp or 6mm imp except blow up bullets and burn out barrels. The VLD bullets will not group well at velocities above 3200fps. You do not want a 1-8.5 twist, go for a 1-9" and for goodness sakes do not get a four groove or three groove anything, especially a cut groove rifle barrel, get a 6 groove button rifle barrel.

Lance
 
I am starting to get really confused. I've been told the following info from the barrel maker and other shooters who use the 6x284.

1. Krieger informed me their 1-8.5 4 groove barrel is shooting the Lupua 105grn Scenar and the Berger 105grn VLD very very well. I've also asked them how these bullets were peforming out of the 1-8.5 4 groove barrel at the higher end velocities from calibers like the 6x284. They said they themselves have been shooting the Lupua and Berger 105's at 3400fps with good results and the super accuatte results with the velocities between 3300 to 3350. I informed the Krieger people of what I wanted to do with this rifle and the speeds I wanted to attain safely with the 6x284. I asked them for their advice and told them I wanted to go with a 1-9 twist barrel. They informed me that the 1-8.5 would be the better barrel for the 6x284. They were adamant about this and said the 1-9 would not be the best choice for the 6x284. I decided to listen to the Krieger people, because they are the barrel makers and know what their barrel will and will not do. Also, the expert I was talking to uses a 6x284 for competition and long range varminting too, and he uses a 1-8.5 4 groove Krieger on his rifle. He also informed me he is using Lapua 105grn Scenars at a velocity right at 3400fps for varminting out to 1000 yards, and for competition he drops the velocity to around 3300fps. He also said he has had no sign of problems with bullets blowing up at speeds of 3400. I also informed them that I would not be using this rifle for high volume varmint hunting, so they knew everything about what I was trying to do with this project. Why would they tell me to use something that would not work. They have always steered me in the right direction, in the past, so I am going to trust them again. They are the professionals and they know what bullets will work out of their barrel and what speeds the bullets will handle out of them.

I disagree with your comment about the 6x284 does not do anything better than a 243AI or 6MMAI does. If that's the case, than why do so many Benchrest and 1000 yard compitition shooters use the 6x284. The Benchrest and 1000 yard competition shooters use it, because they get more velocity out of the chambering over the 243AI or 6mmAI. From what Krieger is telling me, I will be able to push the Lapua and Berger 105's at the 3400fps mark with no problem. This allows me to use the full potential of the 6x284 which gives better velocities than the 243AI or 6MMAI could ever attain. You also said that the the VLD bullets will not group well at velocities over 3200fps. I have heard differently from many shooters who are using the exact same combo using the 6x284 with the Lupua 105's at a little over 3400fps with excellent unbelievable accuracy and as I mentioned before, they are getting better accuracy with the velocities at around 3300 to 3350.

Another thing, with a 6x284 all I have to do is neck down the brass and shoot. I want have to fireform it. The guy with the 243AI and 6MMAI are going to have to fireform brass before they can even begin to do load developement. So your comment about burning barrel's out is a weak argument. The 243AI and 6MMAI guys are going to have to put more rounds down the barrel before they can even begin having fun with it. So this alone makes the 6x284 a better choice over the 243AI or the 6MMAI. The bottom line is all of the top end 6mm are going to be barrel burners. I just wanted the 6x284 because of the following;

1. Gives me the velocity advantage over the 6BR, 6BRX, 6MM Rem, 243AI, and 6MMAI.

2. Brass choice.

3. The 6x284 will anchor the varmints at long range better than the others because of it's velocity advantage.

4. The 6x284 has proven it self in Benchrest and 1000 yard competitions over the years.

5. I've owened one before and it was an awesome chambering.

6. And least but not least, all of my shooting buddies have either 6mm Rem, 6BR, 243, and a 6MMAI. I wanted something different.

The bottom line, the 6x284 is better than the 243AI and 6MMAI for 1000 yard shooting. Don't take my word for it, just look at the 1000 yard bench rest results and see what types of chamberings are being used, I bet you will find a bunch of 6x284's are what most competitors are using and winning with at 1000 yards.

The 6x284, 243AI, and 6MMAI were all designed for speed, so why not use them for what they were designed for. The 6x284 will shoot a 105 and 107grn bullet faster than the 6MMAI or 243AI, so the 6x284 is better for 1000 yard varmint and competition shooting.

Anyhow, I will let you know how it shoots. My guess is, from all the profesional advice I've received and the equipment I am using, it's going to be a tack driver. If you don't know already here is the equipment I am using;

1. 6x284, Match Chamber for Lapua Brass, .272 tight neck.

2. Nesika Model L, 1.700 Diameter Action, Fluted Bolt, Oversized Bolt knob.

3. Krieger, 30", 1-8.5 twist, 4 groove, 1.450 staight cylinder, throated for 105 and 107grn bullets.

4. McMillan Tooley MBR, 5 Pounds lead added, removable front stud for bi-pod use.

5. Jewel 2oz trigger.

6. Vias Muzzle Brake.

7. Davidson 20MOA Scope base.

8. Kelby 30mm Rings.

9. Nightforce 8x32x56mm NXS with MLR reticle.

10. Weight of rifle, 30Lb's.

This rifle will be used for 1000 yard squirrel hunting, so I need it to be steady. This baby should be very steady.
I would like to say thank you to the following people for help on this project;

1. Leroy Johnson of Johnson Precision Gunsmithing. Leroy has been very helpful with this project. He is an awesome gunsmith, and I would have to say one of the best. I have had rifles built buy some of the top smiths in the U.S, David Tooley to name one of them, and I would put Leroy up against anyone of them, he is that good. If you live in California, I highly recommend you use Leroy Johnson for your next project. He is based out of Bakerfield California, his # is (661)304-4165.

2. Nesika Actions-Richard Spruill was very helpful with this project and Action selection.

3. Krieger Barrels-I spoke with about 3 Individuals, at Krieger, who helped me with my decision on twist rate. The one that was very helpful was Mike, THANKS MIKE!! They were very helpful and spent lots of time with me on the phone getting the barrel twist correct for my project.

Wildcat
 
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I, for one, will be thrilled when your project is completed.

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+1
 
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The bottom line, the 6x284 is better than the 243AI and 6MMAI for 1000 yard shooting. Don't take my word for it, just look at the 1000 yard bench rest results and see what types of chamberings are being used, I bet you will find a bunch of 6x284's are what most competitors are using and winning with at 1000 yards.


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First you need to calm down a little.

Second I havent seen many 6-284 shooting in 1k Br matches here on the east coast. At there rate of fire you would be shooting you would burn the barrel out before the season is over. Thats why there are tons of 6mmbr and there wildcatted verions dominating the lines nowadays in the 6mm catagory.

d-a
 
David Tubbs shoots a shotened version of the 243 case or at least that's what he said in his second book.......... /ubbthreads/images/graemlins/confused.gif
 
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