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Posted: 4/23/2016 9:52:08 PM EDT
Speer LE 75 Grain Gold Dot
Following in the footsteps of their successful 62/64 grain Gold Dot LE 223 Remington ammunition, Speer has introduced a 75 grain version of their blind-to-barriers “bonded” soft-point ammunition (#24475). 
This ammunition is loaded in nickel-plated brass cases with crimped and sealed primers, however, there is no sealant at the case mouth. The load is charged with “ball” powder. The head-stamp reads: “SPEER 15 223 REM”. 
The form of the 75 grain Gold Dot is just what you would expect it to be; a longer and heavier version of the 62/64 grain Gold Dots. 
Left to 2.) 62 grain Gold Dot; 3.) 64 grain Gold Dot; 4.) 75 grain Gold Dot. Accuracy I conducted an accuracy (technically, precision) evaluation of the Speer LE 75 grain Gold Dot ammunition following my usual protocol. This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any group-reduction techniques (e.g. fliers, target movement, butterfly shots). The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Also, a control group was fired from the test-rifle used in the evaluation using match-grade, hand-loaded ammunition; in order to demonstrate the capability of the barrel. Pictures of shot-groups are posted for documentation. All shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The barrel used in the evaluation was free-floated. The free-float handguards of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold Competition Series 45x45mm scope adjusted to be parallax-free at 100 yards. A mirage shield was attached to the objective-bell of the scope. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below. 
The Wind Probe. 
The test vehicle for this accuracy evaluation was one of my semi-automatic precision AR-15s with a 24” Krieger barrel. The barrel has a 5.56mm Match chamber with a 1:7.7” twist. Prior to firing the 75 grain Gold Dot ammunition, I fired a 10-shot control group using match-grade hand-loads topped with the Sierra 55 grain BlitzKing. That group had an extreme spread of 0.62”. 
Three 10-shot groups of the Speer LE 75 grain Gold Dot ammunition were fired in a row with the resulting extreme spreads: 1.12” 1.03” 1.05” for a 10-shot group average extreme spread of 1.07”. The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the 30-shot composite group was 0.32”. The smallest 10-shot group . . . 
The 30-shot composite group . . . 
Velocity I chronographed the Speer LE 75 grain Gold Dot ammunition from a semi-automatic AR-15 with a chrome-lined, NATO chambered, 20” Colt M16A2 barrel. 
Chronographing was conducted using an Oehler 35-P chronograph with “proof screen” technology. The Oehler 35P chronograph is actually two chronographs in one package that takes two separate chronograph readings for each shot and then has its onboard computer analyze the data to determine if there is any statistically significant difference between the two readings. If there is a difference, the chronograph “flags” the shot to let you know that the data is invalid. There was no invalid data flagged during this testing. The velocity stated below is the muzzle velocity as calculated from the instrumental velocity using Oehler’s Ballistic Explorer software program. The string of fire consisted of 10 rounds over the chronograph. 
Each round was single-loaded and cycled into the chamber from a magazine fitted with a single-load follower. The bolt locked-back after each shot allowing the chamber to cool in between each shot. This technique was used to mitigate the possible influence of “chamber-soak” on velocity data. Each new shot was fired in a consistent manner after hitting the bolt release. Atmospheric conditions were monitored and recorded using a Kestrel 4000 Pocket Weather Tracker. 
Atmospheric conditions Temperature: 75 degrees F Humidity: 33% Barometric pressure: 30.05 inches of Hg Elevation: 950 feet above sea level The muzzle velocity for the 10-shot string of the Speer LE 75 grain Gold Dot ammunition fired from the 20” Colt barrel was 2652 FPS with a standard deviation of 11 FPS and a coefficient of variation of 0.42%. .... For comparison, here's some additional chronograph data; this time from a Noveske 14.5" N4 barrel. 
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Well... that is awesome. Great accuracy for a SD bullet. no kidding but i'd like to see it thru a more common barrel too. i was only able to get 2moa with ammo through an LWRC 18" DMR barrel/piston upper and i can get 1.5moa with IMI razor with it. molon and his krieger are super natural. so now my question is; how will this bullet perform at lower velocities like we would see at 200-300 yards? |
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no kidding but i'd like to see it thru a more common barrel too. i was only able to get 2moa with ammo through an LWRC 18" DMR barrel/piston upper and i can get 1.5moa with IMI razor with it. molon and his krieger are super natural. so now my question is; how will this bullet perform at lower velocities like we would see at 200-300 yards? Quoted:
Quoted:
Well... that is awesome. Great accuracy for a SD bullet. no kidding but i'd like to see it thru a more common barrel too. i was only able to get 2moa with ammo through an LWRC 18" DMR barrel/piston upper and i can get 1.5moa with IMI razor with it. molon and his krieger are super natural. so now my question is; how will this bullet perform at lower velocities like we would see at 200-300 yards? Apparently on arfcom the manufacturers are full of shit, however, this is what Speer says about the gold dot rifle ammo: Gold Dot rifle bullets are optimized to ensure expansion out of barrels down to 10" at a wide variety of velocities out to 200 yards. You can see the velocity and ballistics gel tests after penetrating through different mediums as well. Speer LE Edit: the 75gr is not there, the 55 and 64 are. |
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Nice work as usual Molon. How close in queue on "the list" is the Hornady TAP SBR stuff? Real curious about it! Since the TAP SBR is intended for use in short barreled rifles, I'm considering testing it from both my standard 20" barrels and a Noveske 14.5" N4 barrel (the shortest barrel that I have on hand.) If the weather cooperates, I should get to it sometime in the next month. ... |
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I don't know if you've experienced this as well Molon but when I was shooting the 75gr Gold Dot I did notice more violent ejection and a sharper recoil impulse vs .223 Prvi 75gr match and .223 BH 75gr OTM out of a 14.5" carbine gas. I asked other people who had experience with this ammo since it might have been my perception and they confirmed that they experienced the same. Ive been told it was because the 75gr Gold Dot's powder burn rate is more optimized for SBRs. I couldnt chrono it myself but some research online suggests this might be the case since the velocity gain from going from a 16" to a 20" barrel is only 46fps.
From Buffman - R.A.N.G.E.'s velocity test of the 75gr Gold Dot: https://www.youtube.com/watch?v=QswX2r6PcxM Chronograph: Pro Chronopal Chronograph Test Taken: 10 Feet Temperature: 43.0°F Humidity: 38% Baro: 30.07"HG Dew Point: 18.9°F Elevation: 849 Feet. All shots are in feet per second (fps) 10" barrel: 1. 2,096 2. 2,096 3. 2,063 Avg: 2,085 724 ft lbs. 16" barrel: 1. 2,614 2. 2,574 3. 2,574 Avg: 2,587 1,114 ft lbs. 20" barrel: 1. 2,656 2. 2,624 3. 2,619 Avg: 2,633 1,154 ft lbs. |
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carbine gas system ... Quoted:
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Are your 14.5s using middy gas or carbine gas? Just curious. carbine gas system ... Ok. I just shot a few thre my 14.5 middy gas. Peakier than 5.56 55gr but not overly so. Less difference than 40 vs 9mm if that makes sense. |
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Here's a sneak preview. 
https://app.box.com/shared/static/rv3jqdryyvhreku2brm06h123pvcnb0q.jpg .... Quoted:
Quoted:
Nice work as usual Molon. How close in queue on "the list" is the Hornady TAP SBR stuff? Real curious about it! Here's a sneak preview.
https://app.box.com/shared/static/rv3jqdryyvhreku2brm06h123pvcnb0q.jpg .... Thanks! Can't wait! |
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Quoted:
Thanks! Can't wait! Quoted:
Quoted:
Quoted:
Nice work as usual Molon. How close in queue on "the list" is the Hornady TAP SBR stuff? Real curious about it! Here's a sneak preview.
https://app.box.com/shared/static/rv3jqdryyvhreku2brm06h123pvcnb0q.jpg .... Thanks! Can't wait! 
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