No Interest In Adding a Target Section?

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rkittine
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Re: No Interest In Adding a Target Section?

Postby rkittine » Tue Jul 26, 2016 9:22 pm

The National Record for 1,000 yard, Bench Rest Score and Group is a 100 (10x10) score with a 10 shot group measuring 2.81 inches or around 1/4 MOA. There are smaller groups shot with 3 or 5 shots, but just getting off 10 rounds at 1,000 yards, means that the wind can change not only multiple times, but at multiple yardages with varied temperature and humidity during the firing. With a muzzle velocity of just under 3,000 FPS, it takes 1 1/2 seconds to get to the target. Fun to pull the trigger and actually watch your round hit the berm 1,040 yards away after passing through the target. A lot can happen in that second and a half.

At 100 yards there is less time for things to effect the projectile and for score, short range Benchrest is shot with one shot put into each of 25 individual targets as some many shooters can put rounds through the exact same hole without being able to tell that there was more than one (or a totally pulled miss) - i.e. 0 MOA accuracy.

As you know, shooting precision at any distance requires a consistency in Shooter, Ammo along with quality equipment, the right cartridge and the ability to read and react to the existing conditions. Certainly easier to shoot a tight group on a windless day, then one with 10 knot winds. So there are only a couple things that we can easily control.

The Equipment - Rifle (action, barrel, trigger and stock), the optics and their set up and the bench equipment.

What Caliber / Cartridge - a 6PPC is the King of short range, but falls way off over 200 yards. 6mmBR is usually best for 300 to 600 yards, but at 1,000 the heavier bullets will better ballistic coeffcients take the lead.

The consistency of the finished loaded rounds.

Great manufacturers and great gunsmiths can turn out the gun. Great component manufacturers can turn out the ammo components, but now they need to be put together so that the shooter now has the equipment to provide the best performance, while it is up to the shooter to gain the skill, but the luck of the draw on the conditions on the day of any shoot or hunt.

I will be happy to start a thread dedicated to how I go about building 20 match bench rest rounds if you or anyone else care to see it. Some of the procedures may not add much in accuracy, but certainly can not hurt.

So a couple of other comments. Lets take the 30 BR compared to the .308 since you have one. It has become well known that small rifle primers provide more uniform ignition than large rifle primers, So the BR cartridges use small rifle primers and for 800 yard or longer F Class, most .308 shooters use the .308 Palma, difference over .308 Winchester, yep, small rifle primer cup. And why is a 30 BR (short .308 Palma) more accurate than a .308? Well you need to fill the case with powder when reaching an accuracy node. Why, think of an under filled case, depending how you handle it will result in how uniform the powder is laid out in the case and how uniform the ignition and burn will be.

My F class rifle is a .308, but I use Lapua Palma Brass and CCI 450 magnum small rifle primers over powders that fill the case.

Bench rest shooters measure powder to .02 grains, including cutting individual granules / flakes etc. and using tweezers to weight them on a scale accurate to .02 grains rather than a tenth of a grain. Both a Gempro as well as a FX 120i are capable to do that, though it will take a lot of effort in a $150 Gempro, but much less in a $650 FX 120i.

So I will start another threat on reloading for precision shooting. Let me know if I should keep it going.

But most important - Where a hat, or your bald spot will show!
BOB ON THE BENCH.JPG
BOB ON THE BENCH.JPG (689.65 KiB) Viewed 894 times



Bob
Last edited by rkittine on Wed Jul 27, 2016 3:47 pm, edited 1 time in total.
Bob Kittine
Sag Harbor and Manhattan, New York
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bluedot
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Re: No Interest In Adding a Target Section?

Postby bluedot » Tue Jul 26, 2016 11:03 pm

Bob, please do, that is start a thread on what your reloading steps are, etc., etc.

I hear you loud and clear on filling the case! Bullet concentricity, proper case prep and consistency, etc., etc.

The Long Range hunting rifle will never be a bench gun - not enough barrel life and with the muzzle brake nobody would want to be within 30 -40 feet of me anyway!

FWIW, here is the build sheet for the Long Range gun:
Nesika Bay Model M Hunter Receiver
Lilja SS, fluted 1-9, 4 groove, 28" barrel, #6 contour
APS Slim Painkiller muzzle brake
Jewell trigger
Manner MCS-GAT stock
Defensive Edge adjustable cheekpiece
HS Precision Detachable Magazine system
Nesika 20 moa SS rail base
NightForce Ultralight rings
NightForce NXS NPR1 5.5-22x50mm with zero stop
Rail mounted ACI
Scope mounted scope level

I started with 200 pieces of brass from one lot (Lapua), but some developed cracks between the neck/shoulder and I'm down to around 175 now. I anneal every time I load now and haven't lost any since I started doing that. I bought enough powder of one lot number to last the life of the barrel, and have enough primers of the same lot too. Bullets, well what I thought would work didn't, so now I have a mixture of Berger VLD's and Wildcat custom bullets. The Wildcat bullets are sorted in 0.1g groups, I haven't gotten around to measuring bearing surface. The Sierra bullets that I was using I can't use now after 200 rounds down the tube. They are going *poof* at about the 50 yd mark at the velocity node where they are/were most accurate.

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rkittine
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Re: No Interest In Adding a Target Section?

Postby rkittine » Wed Jul 27, 2016 7:21 am

Sounds like a nice set up.

Last night I typed for over an hour starting a new thread on this and then lost the internet and it was not autosaved. I will do it in word tonight and then cut and paste it.

Bob
Bob Kittine
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Re: No Interest In Adding a Target Section?

Postby Ramos » Wed Jul 27, 2016 12:09 pm

Forgive me Bluedot, but I have to ask......

How did you find an accuracy node on a bullet that falls apart on the fifty yard line? If they were holding together early on and now they are coming apart, what changed?

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Re: No Interest In Adding a Target Section?

Postby bluedot » Wed Jul 27, 2016 5:52 pm

Ramos, I think the throat roughened up a wee bit and disrupted the jacket on the 175g Sierra MatchKing bullets enough that the RPM pulled them apart at the velocity that I was shooting them at after 200 shots. I called Sierra and talked to one of the tech guys about it, and he had me try a few things. During the third phone call to the same guy he said "Wait a minute. HOW FAST did you say you were sending them down range?" When I repeated the fps, he said "What the hell are you shooting them in? We never EVER shot them that fast." :lolno: If the formula for bullet rpm is Bullet RPM = MV X 720/Twist Rate (in inches) and I'm doing the math right, then the bullet was seeing 279,600 rpm............. :crazy:

I don't let the barrel get hot, and if I can't hold my bare hand on the barrel right in front of the scope I stop shooting and let it cool down. I'll check barrel temp every 1-2 shots.

The accuracy node for the 180g Berger VLD's is 145 fps slower than the 175g SMK's and I haven't had any problems with them. Same powder - WC872. If I use a faster powder, I see signs of pressure before the same velocity is reached.

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Re: No Interest In Adding a Target Section?

Postby rkittine » Wed Jul 27, 2016 6:10 pm

This is on your .308 correct? What twist is the barrel (the 1:9 you stated?) and how much free bore. From what you have said, I assume this is a No Turn neck set up? I think that Berger is recommending a 1:11 for their 30 caliber VLDs.

Bob
Bob Kittine
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Ramos
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Re: No Interest In Adding a Target Section?

Postby Ramos » Wed Jul 27, 2016 6:44 pm

Thanks, Bluedot. That makes sense. I have done bullet RPM calculations before and the numbers are almost beyond comprehension. Makes a guy wonder how any bullet stays together!

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Re: No Interest In Adding a Target Section?

Postby bluedot » Thu Jul 28, 2016 7:33 am

Bob, no, that was on my 7mm Allen Magnum. That is based on a wildcatted .338 Lapua case, with a reduced body taper, shoulder pushed forward and angle changed, etc. It shoves a heavy 7mm bullet in the 3350 to almost 3500 fps range accurately. Loading 108.0 grains of WC-872 behind the 180g Berger VLD gives me 3350 fps at 782' elevation. .010" jump. Yes, this is a no turn neck set up. I was loading 110.0g of WC-872 for 3495 fps velocity with the 175g SMK's and those were going poof after I hit the 200 round count. I can push the 180g VLD's faster, but 3350 fps is where they are the most accurate. Looking at my notes, with the 175g SMK's they liked .010" from the lands too, and every 1.0g of powder generated 60 fps more from 108-110 grains, 111g only showed an 11 fps increase with no pressure signs, but there was no need to try and push them faster. With the 180g Berger VLD's, pushing them faster than 3350 fps showed a decrease in accuracy, so that's where I stayed. A fast miss doesn't accomplish anything.

The gunsmith guarantees 1/2 moa accuracy out to 1,000 yds, but said he had to do that because some guys just can't shoot. He said that with a good trigger squeezer, it will shoot 1/4 moa out that far. I've shot paper groups at 300 yds that were 3/4" c-c, and if I read the wind right, bullets land in the same dirt crater at 1,330 yds. At 1,000 yds, vertical spread on steel hovers between 2"-5", and horizontal can be more if I don't read the wind correctly. That is with 3 shot groups, shooting more than that back to back gets the barrel too warm too fast.

The .308 is an early factory stock (with the exception of a Jewell trigger) FN SPR in .308 that wears the factory 26" tube, 1:12 twist. Yes, 26". Like I said it is an early production model, i.e. mid 2001. It is a controlled feed design, and due to the magazine size, Berger VLD bullets cannot be seated anywhere close to the lands. I bought it from the guy who bought it new who put 16 rounds down the tube and said he couldn't hit a man sized target at 600 yards with it. He gave me the complete gun/scope/bipod and 3 boxes of factory FGM 168g ammo, telling me to take it to the range and if it shoots to my liking, it was mine for what he paid for it back then. With a friend who is a sniper trainer for a state police force who told me what to dial, we went to the range. I ran 3 shot groups every 100 yds from 100 to 1,000 using that factory ammo, but skipped 900 yds due to running out of daylight. It shot consistently 1/2 moa at every distance except 1,000 yds, with that group being 5" wide by 10" tall. I gladly paid the man his money and swapped out the trigger for the Jewell. The scope that he had on it (which it still wears) is a Leupold Mark 4, 3.5-10x40 Mil-Dot, with Badger Ordinance rings and 20 moa base. When the funds become available I will upgrade the scope to a NF, but every time I get close to rat holing away enough $$, something else pops up that needs more attention.

I purchased 700 rounds of virgin .308 Lapua brass at an estate sale, along with a goodly amount of 30 cal SMK's in 168g (800) and 175 g weights (500) and there were 200 180g 30 cal SMK's in the bottom of the box that I didn't see until I got home.

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rkittine
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Re: No Interest In Adding a Target Section?

Postby rkittine » Thu Jul 28, 2016 12:46 pm

Interesting. I would not expect that weight bullet in 7mm to disintegrate.

Bob
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bluedot
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Re: No Interest In Adding a Target Section?

Postby bluedot » Thu Jul 28, 2016 11:57 pm

rkittine wrote:Interesting. I would not expect that weight bullet in 7mm to disintegrate.

Bob


Me either. Sierra techs said I was in uncharted territory. It worked fine for the first 200 rounds, at a MV of 3490 fps. But, the Bergers work fine at 3350 fps now.


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