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Freethinker
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Wow! Smile




“I can’t give you brains, but I can give you a diploma.”
— The Wizard of Oz
 
Posts: 41183 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Had a similar occurrence when I was fireforming 6BR Lapua Brass to 6 Dasher. It was a random receipe …. 30gr of Varget, Hornday something or other projectile, jammed 0.030" into the lands.

That's when I realized the "magic" of the 6mm family and it's performance.

Now with Alpha Brass releasing their 6 Dasher Brass.... fireforming is not required. I have 100 pieces of brass from Alpha waiting to run thru a new Bartlein Barrel that is being turned.

Andrew



Duty is the sublimest word in the English Language - Gen Robert E Lee.
 
Posts: 689 | Registered: May 01, 2010Reply With QuoteReport This Post
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quote:
Originally posted by offgrid:
Another 6BRA chambered by jelrod1, Kreiger 4 groove 8 twist 26" Heavy Palma.

That dog will hunt.
Must be some clean burning powder -- no residue on the target, even at 10 yards. Doh!

How's that gee-tar work going? Doing riffs like Joe Bonamassa yet?
 
Posts: 6384 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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Shooting from barricades isn't my strength. I need more practice if I'm going to play the PRS, NRL, and regional steel match game. Now that the majority of the cattle are no longer grazing on our land, I can set up and leave barricades. Cows have this nasty habit of rubbing up against new structures. And pooping both on and around them.

I put together a test of targets against an old erosion dam. Five of the six plates are visible here, with the sixth one being just out of view to the right. The primary target distances are to the face of the dam, which is the circle on the right and the square next to it.


The diamond on the post is the closest target (#1) and is about 50 yards closer than the dam face. The out-of-view plate to the right (#2) is 25-30 yards closer than the dam. The circle and square (#3 and #4) are within 2 yards of each other in distance. The diamond to the left (#5) is 10-15 yards further than the dam face. The square to the far left (#6) is 35-40 yards further than the dam.

My positions started with prone -- two locations 377 and 355 yards from the dam. Next was a post 340 yards from the dam face. The brown cinder-block-like-thingie is a wood sleeve that fits over the 4x4 post. This raises the shooting position by 11". I have the same setup maybe 200 yards away, in a brushy area just over the top of the right t-post. From this location I shot with either the tripod legs and bags for rear support.


Next was a barricade 320 yards from the dam. I used the either tripod or bags for rear support. The tank trap is just over the top of the barricade.


A tank trap at 300 yards. I used a rear bag support, between my thigh and the buttstock.


Finally, a spool at 305 yards. Shot from the top of the spool.


I dialed the distance for the dam face at each position, then held under and over as I progressed from close to far plates. I calculated the holds from the 377 yard prone position, as I didn't want to carry a huge dope card. Hold unders were 1.5 and .7 MOA, hold overs were .2 and 1 MOA. In theory -- I ended up taking a few extra shots, as the dope didn't always work perfectly from all barricades at all distances.

Wind was interesting. Fishtailing from 5-7 o'clock, at 5-10 mph, varying constantly. I loaded 60 rounds of 69 SMK in mags, shot first with a 24" RRA with a 3-15x scope, then switched to a 14" LWRC with a 2-10x optic. Hit to move on, I finished the course of 36 targets in about 55 rounds with both ARs, then burned the remaining rounds at longer plates from the spool.

I think this will be good practice for future matches.
 
Posts: 6384 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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My target tests at 320 and 440 yards has proven valuable in determining the best ammo for each AR15. I had incomplete data on the 24" DSC barrel with a RRA receiver, so later in the day...

Winds changed later in the afternoon -- finishing at 0-7 mph from 8-10 o'clock.

Hornady 73 ELM had promise, but was a bit variable. The first group at 320 showed vertical stringing, as I often see in transitioning to ELD from other ammo. The first group of five was 3.5", the second one settled down to 1.75". At 440 yards the vertical was 3-1/8".

ADI 69 SMK is just pretty consistent, but generally a slight step down from FGMM. 320 yard verticals of 1-7/8" and 2". At 440 yards it was 3-3/8".

FGMM 69 just works. 320 yard verticals of 2-1/2" and 2-1/4". At 440 yards it was 2-3/8", as follows:


With a few minutes of daylight left, time for Hornady 75 Black. I rushed the first group at 320 yards -- ruhroh -- so we won't discuss it. Still in a hurry, I put 4 rounds in 1-3/8" and was all proud of myself, then yanked a high round for 2-5/8" total for five rounds. OK, time to settle down. With the sun about to set, at 440 yards I dialed a bit too much elevation, tried not to be an idiot, and got the following 1-7/8" vertical group.


If this continues, I probably will reduce my ammo inventory to Hornady 75 Black and FGMM 69.
 
Posts: 6384 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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Given the valuable knowledge gained vertical accuracy testing I did on four of the uppers, I kept it going with my 18" Bartlein -- of course now with the new PRS stock. Winds that day were generally 3-6 mph, with gusts to 8 or 9, switching from 12 to 2 o'clock. A nice day to shoot, but I suspect that morning ranch duties of cutting up downed trees and hauling off the branches didn't help my shooting technique in the afternoon. I also started the practice of jogging out and back to the targets between ammo types -- for measuring results and repainting the steel. As before, measurements are vertical variation only, as wind drift is a whole different matter.

First factory ammo up was ADI (Aussie Outback) in SMK 69. At 320 yards 5-round vertical impact variations were 2-7/8" and 4-1/4". At 440 yards, 3-5/8" and 3-7/8". Decent for this round, but not spectacular. A preview of my day occurred with the first group at 320 yards. Rounds #1 through #4 were 1-3/8" vertical, I got all happy, then yanked #5 low. Cursing, I put round #6 within the area of #1-4. So....unless the winds were funky, round #5 was funky....I yanked the shot. I normally yank high, so low is a new one.

FGMM 69. At 320 yards, 2" and 4-1/4". Dagnabbit, low flyer with round #5 again, putting round #6 with the others. Without the yank the group had 2-7/8" vertical. At 440 yards 2-3/8", 2-3/8", and 3-3/4" verticals.

Hornady 55 Vmax. At 320 yards, 2" and 3". At 440 yards, 3-7/8" and 4-1/4". Not bad. Wind tosses the light bullet however.

Hornady 75 HPBT Match. At 320 yards, 3-3/8" and 5". Crap, low flyer-itis on the fifth rounds. Taking a 6th shot and ignoring sheep-dip shot #5 -- 1-3/8" and 2-1/2". At 440 yards, 5". Taking a 6th shot and ignoring the low flyer on #5 -- 2-1/2" vertical. The ammo works, I didn't that day.

Hornady 75 Black. At 320 yards, 1-1/4" and 3". Another low flyer on the fifth round of the second group, without it vertical of 1-1/4". At 440 yards, 3-3/4" vertical. Again low shot #5, take shot #6, and five rounds in 1-3/4" vertical.

Hornady 73 ELDM. At 320 yards, 2-1/8" and 2-3/4". At 440 yards 4-1/8" and 4-1/4" verticals. No ugly fliers on shot #5 this time. Maybe I'm just tired at sunset, after running a chainsaw and jogging to the targets.

Bottom line -- this is a good barrel. As I saw with 100-yard targets, FGMM 69 is the most accurate round. However as distances increase and winds come into play, Hornady 75 Black is the competition round. Frustrating that I couldn't maintain focus on technique.
 
Posts: 6384 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Freethinker
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quote:
Originally posted by fritz:
As before, measurements are vertical variation only, as wind drift is a whole different matter.


Are you concerned about the effect of “aerodynamic jump” on vertical dispersion in windy conditions?




“I can’t give you brains, but I can give you a diploma.”
— The Wizard of Oz
 
Posts: 41183 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Originally posted by sigfreund:
quote:
Originally posted by fritz:
As before, measurements are vertical variation only, as wind drift is a whole different matter.

Are you concerned about the effect of “aerodynamic jump” on vertical dispersion in windy conditions?

Absolutely.
Wind conditions where I shoot can be challenging. I generally shoot downhill, along a couple of shallow drainages. Elevation drop from shooting positions to targets are usually in the 50-70 foot ballpark. When I go beyond 1000 yards, 80-100 foot drops are the norm. Berms are taller to my left (north), with the land flatter to my right (south). Behind me (uphill and to the west) is a substantial forest of tall pine trees. To the east (downrange) is miles of open and rolling prairie. A large wind farm is just a few miles away.

I am beginning to understand the effects of wind when it blows from relatively consistent locations and relatively constant levels. Twitching directions and variable speeds can give me fits. I often see wind directions change 150 to 180 degrees over the course an afternoon's 3-5 hours of shooting.

On some days I'm just clueless why some shots land high or low -- especially when I know I broke those shots correctly. As in when the reticle just doesn't move off the point of aim during the recoil cycle. I have much to learn.
 
Posts: 6384 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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Now on to the 20" Krieger barrel rifle, with SI Defense receivers. This is the AR I've used in Team Safari, with offgrid being the bolt action shooter. I consider this my most consistently accurate rifle, especially at distance.

The day was chilly. Winds cycling 2-10mph, fishtailing between my 4 and 8 o'clock.

First up, ADI 69 SMK ammo. At 320 yards, verticals of 2-1/4" and 2-1/2". At 440 yards, 2-1/2".

FGMM 69. At 320 yards, 1-5/8" and 1-3/4". At 440 yards, 1-3/8" and 2-1/4". Stepping back to 492 yards, vertical of 2-1/2". FGMM 69 never disapoints with this rifle.

Hornady 73 ELD, what I've used in prior matches. ELD often takes a few rounds down the pipe to shoot consistent groups. This day was no different. At 320 yards, 4-1/2" pattern for the first group on the right circle, 1-5/8" group for the diamond on the left.


At 440 yards. First group in the center target at 3-1/2" vertical, when winds were bouncing around. Second group on the right was 3", with the wind more consistent. Third group on the left, 2" vertical, with total group size of 2-3/8". Realizing that the wind laid down a bit more, this group was shot in no more than 15 seconds.

At 492 yards the vertical was 3-3/4".

Hornady 75 Black, evaluating for future matches. Switching away from 73 ELD often causes a few rounds of accuracy issues, and it occurred here. At 320 yards, first group of 4-5/8" on the left. Second group of 1-1/2" vertical on the right.


At 440 yards, 3-3/4" for the center plate. The wind died for the plate on the right -- I held center of target, fired off 5 rounds in no more than 10 seconds for a 2-3/8" vertical group.

One group at 492 yards was 5-1/4", with winds bouncing all around.

I also shot Hornady 55 Vmax at all distances. Generally a little over 1 MOA of vertical, with a boat load of horizontal from faster and more variable winds.

Bottom line -- FGMM 69 probably has the best accuracy. Hornady 73 will continue as my match round, as it bucks the wind pretty well at distance. Hornady 75 Black offers a good option, in case I want to reduce the types of ammo I inventory -- by eliminating Hornady 73ELD
 
Posts: 6384 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Freethinker
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Nice shooting. Tnx.




“I can’t give you brains, but I can give you a diploma.”
— The Wizard of Oz
 
Posts: 41183 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Based on another local competitor's success with using an SBR in a regional 2-rifle match, offgrid and I went down the path of 223 SBR uppers. Wilson Combat had holiday sales on barrels. I bought a few -- the new SBR, plus down-the-road replacements for my carbines. Offgrid also bought an SBR barrel, likely based on my success with Wilson products.

Offgrid wasn't pleased when his Wilson barrel arrived. The barrel extension measured .996" O.D. IIRC, which would produce a lot a slop with a 1.000" I.D. upper receiver. He sent the barrel back to Wilson for a refund. Offgrid went down a different path, using a custom barrel shop, which produces barrel extensions measuring .999" IIRC. Definitely a tighter fit.

My Wilson 14.5" barrel measured .998" O.D. and thus there was a fair amount of slop in my 1.000" I.D. upper. But I found this is within spec. Hmmmm, not so happy. My gunsmith wasn't overly thrilled about the slop, either. But we decided to move forward with the build. My 'smith considered using some .0005" shims to tighten the fit, but went with his tried-n-true use of red locktite. On to accuracy testing to see if this works...

Initial break-in and zeroing with American Eagle 55 FMJ was promising, especially considering how FMJ generally shoots like crap. But my accuracy with factory varmint and match ammo was just OK -- 5-round groups of .8" to 1.2" at 100 yards. Although I was fighting winds from my left, most of the group-size variation was vertical stringing. Which generally points to crappy technique on my part. Maybe it wasn't such a good idea to run a chainsaw all morning, then shoot in the afternoon.

But then I started hitting my stride with Hornady 75 Black ammo, producing a group of .66". Game on, going to longer distances on steel. Winds now 8-12mph, fishtailing from my 5-7 o'clock, on 12" plates.

320 yards. 1st group on the right -- 3" vertical, 3.5" horizontal. 2nd group on the left -- 2" vertical, 1.5" horizontal.


340 yards -- 1.75" vertical and 2.5" horizontal.


300 yards -- 1.75" vertical and 3.5" horizontal.


Time will tell, but so far with about 100 rounds through the tube, the less-than-ideal barrel to receiver doesn't seem to be too much of an issue.
 
Posts: 6384 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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