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Posted: 8/26/2012 3:25:40 PM EDT
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Doing some load workups with my father in law today for his M1A. We are using 150 gr FMJ BT and H4895. My load workup so far is ten of each
42.4 43.0 43.6 44.2 44.8 Hornady lists 44.0 as the max load but with my other workups have found that their data is on the low side. I have checked other sources and found that most people go up to 46 grains. We were shooting for around 2750 fps Does this data sound good? Should I keep it to 44.0 and lower? Should I crimp? I wasn't planning on it but I do have a Lee FCD Thanks!! Paul |
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That's about the same load I use. H4895 43.0gr Hornady 150gr fmj CCI 200 LR primer Light crimp with LFCD. Velocity was 2740-2750 over my chronograph. No pressure signs, no flattened primers and it shoots as well or better as any factory 150gr load. I need to work up a 168gr load as they seem more accurate, but I got a bunch of 150gr bullets for cheap so it will be a while. |
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If that data is from their "Service Rifle Data " section, then use it in good faith...if not...then, Read these two articles...
http://www.zediker.com/downloads/14_loading.pdf http://www.zediker.com/downloads/oncefired.pdf The M1A / M14 need load data specifically for it, do not use data developed for .308 bolt actions.( Which is what most .308 data is. ) Hot loads Hot loads in M1A's can and do damage the rifle. Sooooo.... read those articles, and then decide for yourself. |
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Quoted:
If that data is from their "Service Rifle Data " section, then use it in good faith...if not...then, Read these two articles... http://www.zediker.com/downloads/14_loading.pdf http://www.zediker.com/downloads/oncefired.pdf The M1A / M14 need load data specifically for it, do not use data developed for .308 bolt actions.( Which is what most .308 data is. ) Hot loads Hot loads in M1A's can and do damage the rifle. Sooooo.... read those articles, and then decide for yourself. Sir,I 've great respect for what Mr. Zediker has to say on the subject of what he calls "loading go the M14" but most of the finer points are lost to those who never intend to use the rifle in service rifle competition. That said there is no secret about the old match standard of 41.5gr of IMR 4895 with a SMK 168 gr bullet. I've also used 42gr with the 175gr SMK. However, the OP's question is IRT is loading for a 150gr bullet. My answer to that question is to direct the OP to the loading tables in the Sierra manual and work up loads from there. I would not disregard precautionary comments Sierra provides in their manual pertinent to reloading for a "gas" gun but within reason the M1A action is quite robust and fully able to accept loadings equivalent to standard military loads that are equivalent for that bullet. 7zero1, out. ETA regarding the question about the need for a crimp: In my humble opinion unless you intend to subject your ammo to storage in a wet foxhole and provided your resized dimension of the case neck inside diameter is between .002" and.003" less than the outside diameter of the bullet you are reloading, crimping is largely futile. |
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The M80 ball load used a 147 gr bullet at about 2750 fps so you are in that same ballpark, but that does not shake out to a specific charge weight. Instead the specification calls for a powder (WC846) velocity (2750 fps) and a max average pressure (50,000 psi). In ammunition production a lot of powder is mixed to meet the required burn characteristics and the charge varies from lot to lot to meet the pressure and velocity requirements.
Canister grade powders are loaded for more consistency,but some variation in charge required to hit a given pressure or velocity is still going to happen. In terms of burn rates and pressure curves, the M14 gas system is non adjustable (in stock form at least) so you want to stay pretty close to home on powder burn rates. The M14/M1A is more tolerant than the M1 Garand, but to keep from beating up the gas system, I would not go any slower than Win 748 and I would not go any faster than IMR 4064. And in that scale BL-C(2) and H4895 are pretty close to center. In that regard, while I have along history with 4895 (mostly IMR, but also the H flavor) I like BL-C (2) in the .308, especially with an M14/M1A for general shooting, in large part as it is as close as it gets to the WC846 powder developed for the M14 and M80 ball. However for 168 gr match loads I really prefer IMR 4064. ––––- Load data is often a little conservative as it may be determined by bullet weight - not by specific bullet. Hornady is a good example of this with a variety of 150 gr to 155gr bullets on that particular page - all with different bearing surfaces, etc. ––––- Hornady has a specific section for 7.62x51 NATO and use an M1A - but only list the 155 gr and 168 gr bullets weights for it, and the results are a bit different than in the .308 section, even though they use commercial brass in each instance. In the .308 section they list a maximum load of IMR 4895 of 64.4 gr with a 2800 fps velocity (apparently with a model 70 test rifle), while in the 7.62x51 section they list a max charge of only 43.4 gr. and 2700 fps velocity. Similarly, the H4895 load decreases from 44.0 in the .308 to 42.9 in the 7.62x51. In the same manner, in the 150-155 gr weight IMR 4064 decreases from 44.9 gr to 43.2 gr. That might be due to the nature of the non adjustable M1A gas system, but I suspect it is due to the concern that M1A shooters may be more likely to encounter and use heavier walled 7.62x51 brass, where a decrease in powder charge is needed to maintain similar pressures. It was something Hornady used to mention (3rd edition), recommending a 1.0 gr reduction) but no longer does (6th edition). –––––– Nosler shows a max load with any of its 150 gr bullets of: 48.0 gr. of IMR 4064 (2920 fps), and 47.0 gr. max load for IMR 4895 (2930 fps) - with no data for H4895. ––––- Sierra shows a max load with a 150 gr. bullet of: 48.2 gr. of IMR 4064 (2900 fps), 44.0 gr. of IMR 4895 (2700 fps), and 48.7 gr of BL-C (2) (2900 fps). Sierra alos recommends reducing the charge by 1.0 gr with military brass. –––––– Speer shows a max load with a 150 gr. bullet of: 47.0 gr. of IMR 4064 (2814 fps), 45.0 gr. of IMR 4895 (2776 fps), and 44.0 gr of BL-C (2) (2607 fps). (and again no listing for H4895) –––––– For the .308 Winchester, Hodgdon shows a max load with a 150 gr. bullet of: 48.2 gr. of IMR 4064 (2900 fps), 44.0 gr. of H4895 (2830 fps), and 49.5 gr of BL-C (2) (2835 fps). And for the 7.62x51 NATO, Hodgdon shows a max load with a 150 gr. bullet of: 43.0 gr. of H4895 (2822 fps), and 49.0 gr of BL-C (2) (2878 fps). –––– IMR shows a max load with a 150 gr. bullet of: 45.0 gr. of IMR 4064 (2786 fps), and 44.0 gr. of IMR 4895 (2794 fps). –––––––– What you need to take away from all this is that the maximum allowable load depends on the specific bullet and variation in bullets weights in the box, the specific lot of powder, the primer, the type of case and variation in the lot of cases, the specifics of the chamber, throat and barrel diameter in your rifle, the size of the expander ball, the neck thickness of the case (both impacting neck tension), whether you roll crimp, taper crimp or don't crimp, the primer used, the ammo temperature, etc, etc, etc. In short, there is no magic number for a powder charge, and even when I find the magic number for one lot, I need to work it up again for the next lot. In that regard, you need to start about 10% below the max load and work up to it slowly while measuring velocity and watching for any signs of excessive pressure. Then think and be conservative as by the time you see even slight signs of pressure, you've already exceeded the pressure limit for the cartridge - usually by at least a few thousand psi. |
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