This cartridge case is the 6mmAR Turbo 40 degree shoulder.It's NOT the regular 6mmAR Turbo.
Since I'm somewhat of an accuracy nut I decided to give this upper a try.
http://www.6mmar.com/
Mine has a DPMS extra thick receiver,26 inch Krieger stainless barrel with 2 inch forward gas port,long free float handgaurd and side charging handle.
My first impression was how well(tight,feels like a perfect fit)the bolt locked up and how handy the side charging handle is.Also the machining in the receiver for the side charging handle and handle itself is flawless.
Next thing was reloading.I resized the 6.5 Grendal parent case to a slight jam fit with a false shoulder for proper fireforming.I took some N-140 off the shelf that's been sittin there for a couple years and decided to take half a grain off some other loads that Robert had listed deciding at 28 grains for the 105JLK's.So in they went at max mag length.I drove to the nearest place I could and fired 3 rounds to make sure they were OK.They were just right so I went home and loaded all 100 cases.
Off to shoot em:
2/23/09:I wanted to test for function and make some fireformed 6mmAR Turbo 40 degree cases for initial loading to do later in the day so I braved some ridiculous winds gusting at 30-40 mph.When getting my first zero at 100 yards,on a shootnsee target,stuck to a five gallon bucket filled with dirt,I noticed immediately that bullets were touching as I moved the adjustments to POA.It's always a good sign when this happens!Dirt was blowing in my eyes and all over my new gun so I only fired 33 rounds.The last 15 or so rushed shots were in just over an inch wide.Zero malfunctions.
When I got home I loaded some test loads with the new 6mm ART40 degree cases using 95Bergers,108Bergers and 105JLK's at max mag length.For powder I used the N-140 and H-380.
Next day:
This time winds were in the 15mph range and I shot at 200 yards.
The H-380 loads were too slow in the 2750 fps for the 105 and 108's.The N-140 loads with the 95B's were really fast for such a small case at 3012 fps with no primer flow.The 105's were 2906 fps and 108's were at 2890 fps.All the 5 shot groups were about the same at 1.5 inches vertical and 2 inches wide.Not bad considering the conditions because my make shift shooting bench and bullets were being blown in the wind as I fired.Again zero malfunctions.
Even though it was windy I decided to shoot all the rest of my unformed brass and thought it would be a good exercise in wind estimation.First I went to 400yards shooting at an 8 inch steel plate painted white so I could see the strikes.I quickly discovered that this was little challenge even in these wind conditions.Vertical was in the 3 inch range
So I set up at 600yards and was still able to hit the plate more than half the time.After hitting the plate the first time the next two shots were almost touching the first for what must of been a 2 inch group!But my group eventually disappeared as the plate had Prob 25 hits on it.Zero malfunctions at 136 rounds using both clips I bought.
Very happy with everything at this stage.
2/26/09,I went out this morning again in 15 MPH winds for further load development at 100 yards shooting 3 different loads using 108B's-R-15 powder at mag length and was disappointed with the results.I was shooting 10 shot groups and they were in the 1 inch range with most of the shots at .75 inch.I'll have to try again at different depths later but it seems that the gun doesn't like them.
Next I tried 2 loads with 105JLK's-R-15 and put 8 shots into .372inch ctc with 2 shots opening up the group to .9 inch with one of the loads.I'll take the blame for the flyers.The gun loved these and I think since I have a bunch of these bullets I will work a little more with them.Average velocity was 2871fps SD was 6.08.I tried one 5 shot group loaded hot with 95B's and got 3076 fps average,SD in the 8's and they went into .8inch ctc.That's the group to the left.Zero malfunctions still.
2/28/09
Myself and 3 other friends went out to shoot long range from 200 to 1000 yards in 100 yard increments at steel in size from 1.5 to 1.8 MOA.Winds were 5-10mph from 30'clock.One friend had a 6.5 Grendel and the other two friends had 223's and 308's.I used the new Berger Bullets BC listed on their site .532 for their 105's in my HV ATRAG ballistic program and was delighted to see that it was pretty much right on for all the distances, +/- a few inches.I noticed the advantage of the extra BC,velocity and accuracy of the 6mmART40 right away because it became delightfully apparent the further out in distance we shot compared to the other rifles and calibers.Suffice it to say that it was easy to hit all the targets for me and very hard past 600 yards for my two friends with their 308's and hard for my friend with his 6.5G past 800 yards.Although to be fair my 3 friends don't have near the long range experience I do,so it mutes a true comparison.I did have one malfunction though,traced to one particularly long nose of one bullet that was lodged in the magazine.I brought along my 6x47L benchrest rifle for comparison.115B's at 3050 fps and I could not discern the difference in wind drift compared to the 6mmART40.I know the 6x47L has superior ballistics but I think more wind would be required to see it.I couldn't be more pleased and am very impressed with the whole system.
The carbine upper is my 15 inch 223 Rem. Armalite
Cartridge on left is a 223Rem on right is a fireformed 6mmAR Turbo 40 degree shoulder.Length is 2.290 inch
To be continued.
Steve
Since I'm somewhat of an accuracy nut I decided to give this upper a try.
http://www.6mmar.com/
Mine has a DPMS extra thick receiver,26 inch Krieger stainless barrel with 2 inch forward gas port,long free float handgaurd and side charging handle.
My first impression was how well(tight,feels like a perfect fit)the bolt locked up and how handy the side charging handle is.Also the machining in the receiver for the side charging handle and handle itself is flawless.
Next thing was reloading.I resized the 6.5 Grendal parent case to a slight jam fit with a false shoulder for proper fireforming.I took some N-140 off the shelf that's been sittin there for a couple years and decided to take half a grain off some other loads that Robert had listed deciding at 28 grains for the 105JLK's.So in they went at max mag length.I drove to the nearest place I could and fired 3 rounds to make sure they were OK.They were just right so I went home and loaded all 100 cases.
Off to shoot em:
2/23/09:I wanted to test for function and make some fireformed 6mmAR Turbo 40 degree cases for initial loading to do later in the day so I braved some ridiculous winds gusting at 30-40 mph.When getting my first zero at 100 yards,on a shootnsee target,stuck to a five gallon bucket filled with dirt,I noticed immediately that bullets were touching as I moved the adjustments to POA.It's always a good sign when this happens!Dirt was blowing in my eyes and all over my new gun so I only fired 33 rounds.The last 15 or so rushed shots were in just over an inch wide.Zero malfunctions.
When I got home I loaded some test loads with the new 6mm ART40 degree cases using 95Bergers,108Bergers and 105JLK's at max mag length.For powder I used the N-140 and H-380.
Next day:
This time winds were in the 15mph range and I shot at 200 yards.
The H-380 loads were too slow in the 2750 fps for the 105 and 108's.The N-140 loads with the 95B's were really fast for such a small case at 3012 fps with no primer flow.The 105's were 2906 fps and 108's were at 2890 fps.All the 5 shot groups were about the same at 1.5 inches vertical and 2 inches wide.Not bad considering the conditions because my make shift shooting bench and bullets were being blown in the wind as I fired.Again zero malfunctions.
Even though it was windy I decided to shoot all the rest of my unformed brass and thought it would be a good exercise in wind estimation.First I went to 400yards shooting at an 8 inch steel plate painted white so I could see the strikes.I quickly discovered that this was little challenge even in these wind conditions.Vertical was in the 3 inch range
So I set up at 600yards and was still able to hit the plate more than half the time.After hitting the plate the first time the next two shots were almost touching the first for what must of been a 2 inch group!But my group eventually disappeared as the plate had Prob 25 hits on it.Zero malfunctions at 136 rounds using both clips I bought.
Very happy with everything at this stage.
2/26/09,I went out this morning again in 15 MPH winds for further load development at 100 yards shooting 3 different loads using 108B's-R-15 powder at mag length and was disappointed with the results.I was shooting 10 shot groups and they were in the 1 inch range with most of the shots at .75 inch.I'll have to try again at different depths later but it seems that the gun doesn't like them.
Next I tried 2 loads with 105JLK's-R-15 and put 8 shots into .372inch ctc with 2 shots opening up the group to .9 inch with one of the loads.I'll take the blame for the flyers.The gun loved these and I think since I have a bunch of these bullets I will work a little more with them.Average velocity was 2871fps SD was 6.08.I tried one 5 shot group loaded hot with 95B's and got 3076 fps average,SD in the 8's and they went into .8inch ctc.That's the group to the left.Zero malfunctions still.
2/28/09
Myself and 3 other friends went out to shoot long range from 200 to 1000 yards in 100 yard increments at steel in size from 1.5 to 1.8 MOA.Winds were 5-10mph from 30'clock.One friend had a 6.5 Grendel and the other two friends had 223's and 308's.I used the new Berger Bullets BC listed on their site .532 for their 105's in my HV ATRAG ballistic program and was delighted to see that it was pretty much right on for all the distances, +/- a few inches.I noticed the advantage of the extra BC,velocity and accuracy of the 6mmART40 right away because it became delightfully apparent the further out in distance we shot compared to the other rifles and calibers.Suffice it to say that it was easy to hit all the targets for me and very hard past 600 yards for my two friends with their 308's and hard for my friend with his 6.5G past 800 yards.Although to be fair my 3 friends don't have near the long range experience I do,so it mutes a true comparison.I did have one malfunction though,traced to one particularly long nose of one bullet that was lodged in the magazine.I brought along my 6x47L benchrest rifle for comparison.115B's at 3050 fps and I could not discern the difference in wind drift compared to the 6mmART40.I know the 6x47L has superior ballistics but I think more wind would be required to see it.I couldn't be more pleased and am very impressed with the whole system.
The carbine upper is my 15 inch 223 Rem. Armalite
To be continued.
Steve
