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SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

 
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Old 07-13-2006, 02:01 PM
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SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

Hello, I've been reading here but haven't posted I don't think. If I have it's been quite a while. Very informed and smart discussion here. SOE does and trains extreme range shooting, mostly for the military guys, and we also run training events for civilians that want to shoot to 2000 yards or more in field conditions. Here is an AAR that I was asked to post here. If i'm out of bounds with this info, I apologize. Comments are invited. Here you are.

AFTER ACTION REPORT: LONG RANGE CLINIC 6-9 JULY 2006

6 July – Overview. The training was attended to 2 shooters. At the last minute, several shooters cancelled due to other commitments. The date of this shoot was released late and didn’t live much time for shooters to arrange for time off etc.

Gun Systems Present: The intent was to include a 338 Lapua rifle in this shoot to compete against the other three cartridges represented. The planned rifle, an Accuracy International 338 LM was not through customs as one of the attending shooters had planned to bring it to the shoot. We will have one for the 22-25 July shoot.

1. .50 BMG – Barrett M107 System with an 8 x 32 x 56mm Nightforce scope on Barrett adjustable rings.
2. .408 CheyTac – M200 full military version rifle with a 5.5 x 22 x 56mm Nightforce scope on Nightforce rings.
3. SOE built 375/408 long range prototype rifle.
4. .408 CheyTac – M310 Civilian Package rifle.


6 July was a planned classroom day. Much of what SOE trains in its programs are not covered by any other sniping or long range shooting program within the US military or other civilian school. The nature of the listed classroom subjects bears witness to this fact.

Much of the classroom instruction takes on the nature of a discussion. There are always many questions and discussion on the answers to those questions. The classroom training went into the early evening. Desktop training on the CheyTac Advanced Ballistic Computer (ABC) was included as SOE believes this to be the best and most advanced computer fire support device for long range shooting on the market today. All of the long range shots were done with the use of the ABC to generate the Elevation and Windage settings for the rifles.

Care and Maintenance of Big Bore Rifles
Special Marksmanship Practices of Extreme Range Shooting
Determining the Effects and Correcting for Meteorological and Environmental Effects
Ammunition Management for Long Range Shooting
Ammunition Selection from Issued Cartridges – DELETED DUE TO TIME CONSTRAINTS
Construction of High Precision Cartridges for Long Range Shooting – DELETED DUE TO TIME CONSTRAINTS
The Theory of “Error Budget Long Range Shooting” – DELETED DUE TO TIME CONSTRAINTS
Internal Ballistics Factors of Long Range Shooting
Introduction to the Ballistic Data Tables and Gun Integration
Collecting Critical Gun Data for Data Table Integration


7 July

The rifle zeros were done at 525 yards. It is not critical to have a fixed “even” known distance when zeroing with the CheyTac ABC, but you do have to know the range to the target. We frequently use uneven range values (525 yards) to do the zeroing so that the shooter is in the best ground position available. When you zero the CheyTac ABC to the rifle, you simply enter the range to the target in yards or meters, enter the air temperature, air pressure, ammunition temperature (to adjust for muzzle velocity values), the guns muzzle velocity and then adjust the elevation knob on the scope to match the elevation setting generated by the computer for that shot. Then the ABC and the gun are in “tune” as is the shooter’s particular individual zero. (More info on this method on the upcoming SOE / CheyTac ABC page on SOE’s website.

All guns were chronographed on the South Creek range before zeroing. Muzzle velocities obtained were:

Barrett M107 .50 cal – HSM AMAX ammo – 2660 fps
M310 .408 – 419 gr. HB – 2860 fps
M200 Military Package 408 CheyTac – 419 gr. HB – 2860 fps
375/408 SOE – 350 gr. LRBT M40 Match – 3265 fps

Zero Guns at 500 Yards – All rifles shot 1 MOA groups with ease. M107 with AMAX was at 1.4 MOA.

Long Range Grouping Exercises 525, 1125, 1525 Yards – The 408 and the 375/408 were the easy winners in this shoot. These guns are designed for superior stability and shoot ability. The M107 is challenged directly by those two shooting standards. The M107 however did respectably well shooting 1.5 MOA at these ranges. SOE’s director shot the rifle during these drills. SOE has extensive experience going back to 1993 training Special Forces snipers on the shooting and marksmanship demands of the Barrett rifles. SOE trained Barrett shooters are guaranteed to be 1.5 MOA and better shooters when using quality match ammunition. The day was ended at 1525 yards due to time constraints.

The CheyTac ABC was used to control the fire of these guns. We went from 525 to 1125 to 1525 yards using the ABC to generate the elevation and Windage settings at these ranges. We did not walk rounds in to the target, which is expensive on ammo costing $4.00 a shot. The ABC generated dead accurate elevation settings that would have resulted in X and 10 ring shots for elevation at all three ranges.


8 July

South Creek Range – 2025 yards. In the morning, we started with cold gun shots at 2025 yards at the South Creek range. The M107’s supersonic range was questionable at this distance so we did not group the M107 at this range. We also wanted to proceed directly to the mountain range to shoot unknown distance. The 408 CheyTac M200 gun and the 375/408 SOE gun both shot 1 – 1.5 MOA at the 2025 yard mark. The 375 however, had a significant advantage as these ranges. Data below:

375/408 – Elevation setting for 2025 yards – 43.75 MOA from 100 yard zero. Velocity @ 2025 = 1822 fps – 2.50 seconds flight time.

408 CheyTac - Elevation setting for 2025 yards – 64.50 MOA from 100 yard zero. Velocity @ 2025 = 1404 fps – 3.06 seconds flight time.

(For comparison) M107 / AMAX @ 2660 fps – Elevation setting for 2025 yards – 75.25 MOA from 100 yard zero. Velocity @ 2025 = 1309 fps – 3.30 seconds flight time.
__________________________________________________ ______________

8 July - From South Creek, we moved to our steel target long range located near King Mountain, in central Idaho. Elevation is about 7500’ ASL. Air pressure was 23.65 In. Hg. With an air temperature of about 92 deg. F. This range consists of 15 steel targets at ranges from 1000 yards to 2245 yards. The targets vary from 20” x 40” to small targets of 14” x 14”. The big targets are not the more far in range, and the small targets are not the closest ones. The shooting positions here are challenging as they are in field condition.

Shots at targets in the 1500 yard plus ranges require that the guns be elevated to the long extent on their bipod legs or rucksacks. This creates inherent instability that shows each gun's weakness in design and execution. The bipod above the barrel design is superior in this environment. Guns like the M107 with its unstable below the gun design have severe limitations in this environment. The result is usually a lot of vertical stringing of the shots and unpredictable results.

All three represented cartridges have high BC values. (AMAX - .952) (408 CheyTac - .945) (375/408 SOE – 1.018). These high performance rounds all had the ability to attack targets at all but the 2245 ranges. At this range, only the 408 and the 375/408 were able to compete. The gun design limitation on the M107 had a drastic effect on the gun’s ability to be accurate for 1st or 2nd shot engagements on targets. A 12” steel target was attacked successfully at 1475 yards with multiple shots using the M107/AMAX combination. (Multiple shots at 1475 were placed at about 1.5 MOA and less). It should be noted however, that military ammunition including the Mark 211, MOD-0 Raufoss round could not be expected to do as well.


9 July – King Mountain location. We returned to the field shoot range. We had planned on shooting another gun position, but decided to remain with the current spot to improve on non-standard gun positions, unstable positions and the demanding terrain at GP2.

The field shoot range is most demanding on the elevation and Windage settings. The terrain here is extreme and as depicted in the photos, resembles terrain in Afghanistan and eastern Iraq in the mountainous border region of Iraq/Iran and North Korea for that matter. SOE does not doe “chasing shots”. Meaning we do not guess at the range and then use historical “data books” to generate an elevation and Windage setting for the gun and shots. Personally, I have not kept a historical shot record for several years. SOE trains that historical records mean very little when you are not shooting in a meteorological environment that you have never been in. All the data books kept in the US will do a professional sniper any good when they go to the Middle East or the Korean peninsula.

In a wrap, the position at King Mountain range demands the following:

1. Gun systems that are supersonic to 2400 yards at these conditions.
2. Computerized fire support to generate accurate elevation and Windage settings for 1st and/or 2nd shot engagements.
3. Super accurate and high BC bullets and ammunition to give you the ability to shoot these ranges.

SOE is doing this shoot again from 22-25 July. The 338 Lapua will be included in that shoot using 250 gr. Scenar bullets, 250 and 270 gr. LRBT J40 match bullets and 300 gr. Sierra Matchkings as well.

Short analysis: The 375/408 and 408 CheyTac are both vastly superior to the M107 rifle and the AMAX projectile. Unfortunately the military is not using the AMAX load except in a couple of small circles. The AMAX is a very capable bullet, but needs more velocity than can be generated by the M107 or other bolt action 29” barrel .50 cal. Rifles to be effective. Supersonic range and flight time are the key figures and the 408 and 375/408 are superior in those values. The 338 Lapua is a key player also, if using the 270 gr. LRBT projectile at 2800 fps or more speeds.

The 375/408 is the current supersonic range king at a supersonic range of 2930 yards at sea level conditions and a velocity of 3265 fps.

Testing and analysis will continue throughout July and into August on these cartridges.

SOE Home Page

SOE After Action Report

triggerfifty@hotmail.com

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Old 07-14-2006, 07:55 PM
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Re: SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

T50, thanks for the post,very interesting stuff.what really caught my attention was the 375/408.i'm relatively new to the long range stuff but my belief is this might be hard to beat for big game huntable killing power.you say the lost river bullets worked pretty well.that seems to be the problem with the bigger calibers.there are a couple others in 408 but 375 is not as popular.how good do these 375 bullets shoot?

PS looks like a great place to streach things out a bit!
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Old 07-15-2006, 09:38 AM
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Re: SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

You're welcome. Sorry for the delay on getting back to you. Atomic days in town, worked the rodeo last night. The 375/408 and the 408 as well are exceptional big game killers. Lost River Ballistics, whose real specialty is big game bullets (J36) and members of this site know them, are very successful. The hunting bullet J36 is 400 gr. for the 408 caliber (@ 3000 fps) and the 375 is a high BC .640 300 grainer that would probably do about 3400 fps easily enough in a 375/408 rifle. The Lost River BCs are accurate on their site. We have shot many of them at Yuma Proving Ground in front of a doppler radar to measure downrange stability and performance and their numbers if anything are on the low side of the real BC.

Most manufacturers, except Sierra, do a mathematical calculation that is usually lower than the measured BC. The Hornaday AMAX .50 is an example. They claim over 1.050 BC, but in actual flight testing, the BC is around .950.

The accuracy of the M40 and J40 match projectiles is exceptional. They must be shot down the right barrel setups. Because of the alloys and length of the match bullets, you usually need a faster twist. Don't worry about that with the J36 bullets.

Lost River Ballistic Technologies
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Old 07-15-2006, 04:18 PM
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Re: SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

T50, i guess the 350 gr 375 cal is only for the mil/law.you posted a BC of over 1. what twist would this bullet need? i'm very familiar with the precise fit these bullets need, it's their biggest drawback.they'll only work IF the fit is perfect and then they haven't shown they can shoot as good as jacketed bullets.
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Old 07-15-2006, 05:21 PM
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Re: SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

In reality, there are only 3 or 4 bullets that measure a true 1.000+ BC. The others are .50 BMG rounds. I disagree wholly with you on 2 aspects. First, that these need a perfect fit. That is true for bore-riders. No, these need a specific land/groove configuration. Many match barrels are "tight" that squeeze a paper puncher bullet tight and force it down the bore under intense pressure. A machined bullet doesn't need this swaging to be accurate, but it does need a barrel with specs built for it, as DO match jacketed bullets.

Second, I've been shooting these solids for 5 years now and I can't find another jacketed bullet that will outshoot them. All I do is 1500+ yard shooting, there are few bullets and guns that shoot in that world well. I shoot a 338 Lapua and have shot the 250 SMKs, Lapua scenars, D46 FMJBTs, 300 SMK and some special stuff now and then. In shooting the 270 gr. and 250 gr. solids, they don't match up for accuracy or for long range performance anything near 2000 yards.

The twist in these guns is 1:11". K&P barrels shoot them, Lothar Walther barrels shoot them, Lawton barrels shoot them, and a few others. What doesn't shoot them are tight bores like Obermeyer, Krieger etc. that super swedge jacketed bullets. Different engine, different gas.

But on the fit? Nah, gotta disagree. There are lots of misconceptions and mistruths out there about these solids. You just have to put them down the right barrels. You wouldn't put a 220 SMK down a 1:12" twist slop bore right? Good discussion though.

Later,
Trig
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Old 07-16-2006, 06:34 PM
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Re: SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

i guess you seem to agree with me that these bullets need the right combination to shoot.you've listed some barrels they won't work in because they run a little small.yes match bullets work very well in them, but they'll also work in the other barrels you mentioned and even production quality barrels because they're soft enough to slug up into whatever size the bore is.a solid won't work if the bore is too snug and they also won't work if it's just a little loose.again because they won't slug up.this to me means they need a very precise fit.

as far as accuracy goes every one on here has heard about them being accurate.i'm referring to Lost River bullets.every year there's rumor of someone with LR bullets gonna clean up at Williamsport, 1k, or at some of these mile shoots.every time i talk to some of the competitors it just doesn't happen.i think they'll shoot very accurately out of the "right" barrel.(perfect fit [img]/ubbthreads/images/graemlins/grin.gif[/img]) to my knowledge it hasn't been proven they'll outshoot jacketed lead bullets at any range. would love to see a great hunting, high BC bullet in 375 that would shoot lights out.

i believe in solids for hunting but not for long range hunting.i dought if there's anyone on here that believes they have the accuracy or the terminal performance needed for long range.

i'm not trying to flame, i'm actually very interested in your reports and speciffically anything you have with those 375 bullets.can a fellow get ahold of those 350 gr projectiles or do you need a security clearance with George's signiture or something?
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Old 07-18-2006, 02:25 PM
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Re: SOE Long Range Shoot AAR 375/408 v 408 v 50 BMG

"What doesn't shoot them are tight bores like Obermeyer, Krieger etc."

Broad statement that? Could you expand a little bit there Deano? Obermeyer runs deeper grooves on some calibres, and his groove circle is not all that tight, he just bore reams shallower than the rest, Krieger runs pretty much Saami std unless they state tight bore, so are you saying the et cetera includes barrelmakers who run saami std wont shoot the bullets? intrigued to say the least..I will say this, it would be easier to tell Krieger to run a couple tenths bigger on groove than it would be to tell a buttoneer..

JR
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