Are you sure that your load is 25.0 grains of TAC? That is 1.6 grains over book maximum.Originally Posted by 03RN
Are you sure that your load is 25.0 grains of TAC? That is 1.6 grains over book maximum.
-Seconds Count. Misses Don't-
Sorry, 24gr. 24.8 is book max for 556.
On the ragged edge of the world I'll roam,
And the home of the wolf shall be my home - Robert Service
I never got the Velocity I wanted from Varget with 77gr SMK. Accuracy was solid, but I was trying to get distance from it. When I tried CFE223 it was never accurate for me, and I tried for a bit with it. Maybe I just wasn't getting my life together right for it. I ended up with AA2520, and I got accuracy and distance from that. My exact load escapes me, but I think I was around 25.0gr, plus or minus one or two tenths. (Check the load manuals, obv.) That load ran like gangbusters out of my 18" SPRish thing, and I never bothered trying to find another load for it.
When purchasing in bulk, the Hornady 75 grain BTHP Match has historically been found at a slightly lower price than the Sierra MatchKing and the Hornady bullet can be hand-loaded to nearly the same level of precision/accuracy as the MatchKing.
The Nosler 77 grain OTM can at times be found at a lower price than the Sierra 77 grain MatchKing and the Nosler bullet has better terminal ballistic properties than the 77 grain MatchKing, though it's never been as accurate in my barrels as the MatchKing.
Reloading For The AR-15: Hornady 75 Grain BTHP
Hornady produces three different versions of their 75 grain open-tip-match bullet in 22 caliber (0.224”). For this article, we’ll be looking at the projectile that is colloquially referred to as the “T1”.
The T1 is available as a reloading component, with a product number of #2279 for the 100 count boxes. It’s also available in 600 and 4000 count boxes.
I use the Hornady 75 grain BTHP bullet to load match-grade hand-loads for my semi-automatic AR-15s chambered in 5.56mm/223 Remington. According to Ballistic Performance of Rifle Bullets by Bryan Litz, the Hornady 75 grain BTHP has an average G1 ballistic coefficient of 0.356 and an average G7 ballistic coefficient of 0.183.
The lot of T1 projectiles used for this article have a nominal length of 0.988” and I load them to a nominal COAL of 2.245”. When fired from a Colt SOCOM barrel with a 5.56mm NATO chamber, this COAL will create a jump to the lands of 178 thousandths of an inch. When fired from a Larue Stealth barrel with a 223 Wylde chamber, this COAL will create a jump to the lands of 115 thousandths of an inch and when fired from a Krieger barrel with a 223 Remington chamber, this COAL will create a jump to the lands of 78 thousandths of an inch.
The jump to the lands figures stated above where obtained using a Sinclair bullet seating depth gauge and a Forster 223 Remington 1.4636” head-space gauge. These figures are contingent upon a variety of variables, such as the particular chamber reamer that was used for your barrel, the number of rounds that have been fired through your barrel when the measurement is obtained, the particular lot of bullets used and whether you use a virgin case, a fired case, a resized case or a head-space gauge to obtain this measurement.
WARNING!
Reloading is an inherently dangerous activity. The information provided here is for educational purposes only. It is not intended to be used for the actual loading of ammunition by the reader. No warranty, guarantee or assurance that these loads are safe is stated, suggested or implied nor should any be inferred. Usage of this information for the actual loading of ammunition may result in malfunctions, damage and destruction of property and grave injury or death to beings human in nature or otherwise. Don't even view this information in the presence of children or small animals.
For this hand-load of the Hornady 75 grain BTHP bullet, I use virgin Lake City brass that has been weight-sorted, match-prepped and neck-sized. The cases are primed with Federal GM205M primers and charged with VihtaVuori N140 powder and as mentioned above, the T1 projectile is seated to a COAL of 2.245”. This process is conducted in a semi-progressive manner on a Dillon XL-650 press using a digital electronic powder dispenser and scale to dispense a powder charge of 24.1 grains of the VihtaVuori N140.
When chronographed from a 20” Colt A2 barrel, a 10-shot string of this hand-load fired over an Oehler 35P produced a muzzle velocity of 2638 FPS with a standard deviation of 4 FPS and a coefficient of variation of 0.15%. (The muzzle velocity was calculated from the instrumental velocity using Oehler Ballistic Explorer.) A 10-shot group fired from one of my Krieger barreled AR-15s, at distance of 100 yards using my bench-rest set-up, had an extreme spread of 0.526 MOA.
No canines were harmed during the testing of this ammunition.
….
Nosler 77 grain Custom Competition
Nosler introduced their 77 grain Custom Competition BTHP bullet as an obvious competitor to the 77 grain Sierra MatchKing. The shape and ballistic coefficient of the Nosler bullet is very similar to that of the Sierra MatchKing. The Nosler bullet does have one major difference from the Sierra MatchKing; it is constructed using the thinner J4 copper jacket.
I recall an early Nosler advertisement for their Custom Competition bullet that included a phrase saying the bullet was “ideal for military and law enforcement,” hinting at the possibilities of improved fragmentation due to the thinner J4 jacket.
Thanks to the works of Dr. G.K. Roberts we know that the 77 grain Nosler bullet loaded to mil-spec velocities has superior terminal ballistic properties to that of the 77 grain Sierra MatchKing loaded in MK262. The terminal ballistic properties of the 77 grain Nosler bullet rival that of the Hornady 75 grain 5.56 TAP load. Unfortunately, there are no ammunition manufacturers that I’m aware of currently loading the 77 grain Nosler to mil-spec velocities.
The Nosler 77 grain Custom Competion bullet is typically sold without a cannelure, however Nosler occasionally releases the bullet with a shallow cannelure similar to the one found on the 77 grain SMK loaded in MK262. The cannelured version of the 77 grain Nosler will be the focus of this report.
For the first phase of testing, I hand-loaded the cannelured version of the 77 grain Nosler BTHP to a typical SAAMI velocity (approximately 2600 fps from a 20” Colt barrel) to establish an accuracy baseline. No case mouth crimp was applied at this phase.
As per my usual protocol, accuracy testing was conducted from a concrete benchrest at a distance of 100 yards. For this phase of testing I used one of my 1:7.7” twist Krieger barreled AR-15s . This barrel has produced sub ½ MOA 10-shot groups with my hand-load topped with the Sierra 55 grain BlitzKing. The fore-end of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rode in a Protektor bunny-ear rear bag. A Leupold Competition Scope was used for testing. Wind conditions were monitored using a Wind Probe.
Three 10-shot groups were obtained which had extreme spreads of
0.797”
0.827”
0.812”
for a 10-shot group average of 0.812”. The three groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The composite group had a mean radius of 0.26”. This test shows that the Nosler bullet itself is capable of consistent sub-MOA accuracy at 100 yards when fired from a semi-automatic AR-15.
For the second phase of testing, I safely worked up a load for the 77 grain Nosler BTHP to a muzzle velocity of 2800 fps from a 20” barrel using a non-canister grade military powder which has a velocity-to-powder-charge ratio that is very close to that of the powder used in MK262. No case mouth crimp was used in this phase of testing either.
Since my Krieger barreled AR-15 has a 5.56mm Match chamber that is “a little too tight” for mil-spec pressure loads, I used my AR-15 with a 20” Noveske DCM barrel with a 1:7” twist for this phase of testing. This Noveske barrel has the “Noveske Match Mod 0 chamber which is designed to offer 100% reliability while retaining maximum possible accuracy. The chamber body is slightly larger than the 5.56mm NATO minimum, but within the 5.56 NATO tolerance. The throat is redesigned for proper bullet alignment with the axis of the bore. This chamber was developed to fire MK262 Mod 1 on AUTO in hot environments." This barrel has produced sub ¾ MOA groups with my 55 grain BlitzKing hand-load.
Accuracy testing using the Noveske barreled AR-15 and the mil-spec velocity load of Nosler 77 grain was conducted in the same manner as described above in the first phase of testing. Three 10-shot groups were obtained from 100 yards. Those groups had extreme spreads of:
0.880”
0.857”
0.845”
for a 10-shot group average of 0.860”! These groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group which had a mean radius of 0.29”.
For the final phase of testing I added a taper crimp to the case mouth of the previously described load used in phase two. A 10-shot string of this load fired over the Oehler 35-P chronograph from my 20” Novekse barrel had a muzzle velocity of 2801 fps with a standard deviation of 12 fps.
Three 10-shot groups fired from 100 yards from the 20” Noveske DCM barrel had extreme spreads of:
1.033”
0.914”
1.241”
for a 10-shot group average of 1.063”. As before, the three groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the composite group was 0.31”.
For comparison, Black Hills MK262 Mod 1 fired from my Lothar Walther barrel AR-15 had a 10-shot group average extreme spread of 1.098”. The mean radius for the 30-shot composite group of MK262 Mod 1 was 0.33”.
…..
Last edited by Molon; 01-05-2024 at 10:27 PM.
Member of the General Population
A goldmine of good information. Thanks!
"Government is not reason, it is not eloquence, it is force; like fire, a troublesome servant and a fearful master"
FWIW I’ve been using the max load for 8208XBR and either the SMK or Nosler factory 2nds bullets over CCI#41 or S&B sr primers for years. I’ve forgotten the chrono data and the comeups are in my log book, but I can get good hits out past 600 yards with either bullet from my two 20” AR shaped rifles.
With 8208XBR being hard to source I’ve played with Hodgdon’s CFE Rifle and RMR’s 75gr match-ish bullet, they are useable at max loadings when lit by a magnum primer. But I still get the odd flyer that keeps me from being a glowing reviewer.
I have tried the 69 RMR 3GH but results have not been as consistent as a blem 77 SMK. One 5-shot group will be .5" and the next two will be 1.5 or 2". Still more consistent than a 55 FMJ, and they fly a lot better at longer ranges. Funny thing is, I bought some of their first run and blems, and I can't see the difference between them.
-Seconds Count. Misses Don't-
Thanks @Molon - that’s some really good gouge. I’ll keep an eye out for both of those projectiles.
This load has worked well for me in all my rifles in 5.56/223. 21.5 to 22 grains depending on lot of VV N135 with 77 smks loaded with CCI primers.
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