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Posted: 11/2/2013 10:24:28 AM EDT
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I am trying to find some load data for reloading 7.62x51. I am using Lake City brass and 147 gr surplus FMJBT. I have used H335 and Win 748 powder in the past. I just purchased Hodgdon CFE223. I have found info on 150gr and 130gr. But no info on 147gr. If any one is using this powder would you provide me with some feed back. Here where I live finding powder can be a hard time. So I try to use what I can find.
Thanks Dave |
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I am trying to find some load data for reloading 7.62x51. I am using Lake City brass and 147 gr surplus FMJBT. I have used H335 and Win 748 powder in the past. I just purchased Hodgdon CFE223. I have found info on 150gr and 130gr. But no info on 147gr. If any one is using this powder would you provide me with some feed back. Here where I live finding powder can be a hard time. So I try to use what I can find. Thanks Dave You will be MUCH better served in the reloading forum. Here, every recipe will be for 87 grains. |
| This has some interesting info on Lake City M80 loads. CMP Forum Link. |
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You will be MUCH better served in the reloading forum. Here, every recipe will be for 87 grains. Quoted:
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I am trying to find some load data for reloading 7.62x51. I am using Lake City brass and 147 gr surplus FMJBT. I have used H335 and Win 748 powder in the past. I just purchased Hodgdon CFE223. I have found info on 150gr and 130gr. But no info on 147gr. If any one is using this powder would you provide me with some feed back. Here where I live finding powder can be a hard time. So I try to use what I can find. Thanks Dave You will be MUCH better served in the reloading forum. Here, every recipe will be for 87 grains. You will not find load data with the 7.62 heading, it will called 308 Win as the two are Identical. |
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Note that the SAAMI pressure for .308 Win is higher than the maximum pressure for 7.62X51 ammunition. However, 7.62X51 brass is heavier than commercial .308 Win brass, hence has less internal volume and can produce higher pressures than the same charge and bullet in commercial brass. So use .308 Win data, but reduce the load by a grain or two to start. If you are shooting an M1A, don't use maximum .308 Win loads. |
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Loading .308/7.62 you really have to pay attention
to case capacities and primer type (standard vs. magnum). I load for M1A and only use IMR 4064, so it's hard to over power a load to catastrophic failure, but too hot loads will over wear the rifle. Research case capacities for all your brass, I usually have to drop a grain in LC and CBC w/NATO mark to keep same POI. |
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Note that the SAAMI pressure for .308 Win is higher than the maximum pressure for 7.62X51 ammunition. However, 7.62X51 brass is heavier than commercial .308 Win brass, hence has less internal volume and can produce higher pressures than the same charge and bullet in commercial brass. So use .308 Win data, but reduce the load by a grain or two to start. If you are shooting an M1A, don't use maximum .308 Win loads. What is SAAMI Max pressure for these two? Links to SAAMI specs would be helpful. |
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You know as well as I do that SAAMI does not list chamber pressure for 7.62X51 cartridges, and I'm 99% certain you have the information for CUP and piezo pressures on tap. The NATO allies use 415 MPa, which the CIP uses for both 7.62 NATO and .308 Winchester. That converts to 60,191 psi, but the CIP measuring system sets the sample point further forward in the case, so it sees a bit of the pressure drop at the bullet base that occurs when the bullet starts moving. That makes them tend to read about 2,000 psi lower than the SAAMI setup does in this pressure range. So the same ammo would measure closer to 62,000 psi in SAAMI equipment. There are for all practical purposes identical. And I'm almost certain you know that a 7.62 NATO cannot match a 308 Winchester's ballistics while operating at a 12,000 PSI handicap, yet they are ballistically identical Common sense, dictates that if fired from the same rifle and velocities are the same then Pressures are the same. Please explain how these two can have identical ballistics if one is operating at 12,000 psi less pressure? http://www.midwayusa.com/product/953713383/federal-american-eagle-ammunition-762x51mm-nato-168-grain-open-tip-match http://www.midwayusa.com/product/953358610/federal-premium-gold-medal-ammunition-308-winchester-168-grain-sierra-matchking-hollow-point-boat-tail |
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I wouldn't shoot loads made with CFE223 in my M1a. Powder is much slower than the rifle was designed for so you'll be working your gas system harder than it was made for.
If you're making ammo for an AR10 or FAL, then go for it. Hodgdon reloading center has start & max data listed for CFE223 for .308. Start low and work up because some of those max loads are fast and look hot! |
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I am trying to find some load data for reloading 7.62x51. I am using Lake City brass and 147 gr surplus FMJBT. I have used H335 and Win 748 powder in the past. I just purchased Hodgdon CFE223. I have found info on 150gr and 130gr. But no info on 147gr. If any one is using this powder would you provide me with some feed back. Here where I live finding powder can be a hard time. So I try to use what I can find. Thanks Dave Ever consider buying some manuals? |
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Dave,
Short answer is use the 150gr data. Hornady does list "Service Rifle Data" which IS 7.62x51 is it not? The rifle used to create the data was a M1A. The 8th edition does not show any data for CFE 223 though. Maybe somebody with the 9th edition will post. CFE 223 in a M1A? I can't say. |
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CFE 223 will not produce proper gasport pressures for an MIA, and the MIA has a kinda anrrow acceptable gasport pressure range needed for operation.
To much port pressure and you will beat the M14 / M1A operating rod to death , to little and it will short stroke .... bottom line is not all .308 / 7.62x51 powders are suitable...and CFE 223 is one that isn't quite right., in a M1A....and thats to bad ,believe me , I wish it would.. If you are loading for a M1A, there are all sorts quirky issues.... that we can help you with. In a bolt action it will be no problem. That said , I haven't tried it in a AR10. Davidc56, what rifle are you reloading for ? |
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Even if the chamber pressures were the same and the same pressure measurements used, the military ammunition and civilian ammunition are pressure tested in different chambers. The chamber dimensions are different. That said, most commercial ammunition is loaded UNDER maximum poressure because they have no control of the condition of the firearms,that customers use. Military ammunition is often loaded near the upper limits for maximum performance and the military presumes modern, well maintained firearms are being used.
The published service rifle load data for 150 and 155 grain bullets will work for 145 and 147 grain bullets. Gas port pressure is as much an issue as chamber pressure and this usually isn't considered with commercial ammunition. Here is some published service rifle load data. NRA 1981 military duplication loads, based on muzzle velocity from an M1A with a military barrel with a military chamber. All loads in military cases, based on muzzle velocity only, but powders chosen to be acceptable for the gas system. 150 grain bullets - LC cases IMR-3031 - 42.0 grains (this load is hot in military case) IMR-4895 - 42.5 grains IMR-4064 - 43.0 grains W748 - 46.0 grains (this load is hot in military case) NRA 1984 service rifle load data, developed in a 24 inch Remington pressure test barrel, based on chamber pressure only. (May be using commercial SAAMI chamber) Pressure limit, "around 52,000 CUP." Factory military M80 ammunition with 149 grain bullet for reference - 2829 fps - 48,700 CUP 147 grain bullets - LC cases IMR-4895 - 42.0 grains - 2775 fps - 48,200 CUP H4895 - 42.5 grains - 2770 fps (Note this was the old pre-1999 made in Scotland powder and not current made Australia powder.) H335 - 43.0 grains - 2770 fps 150 grain bullets - LC cases 40.5gr IMR-3031 – 2728 fps – 47,400 CUP 41.5gr IMR-3031 – 2793 fps - 51,000 CUP 41.0gr IMR-4895 – 2726 fps – 49,100 CUP 42.0gr IMR-4895 – 2784 fps – 51,600 CUP 41.0gr H4895 – 2694 fps – 46,500 CUP 42.0gr H4895 – 2743 fps – 48,800 CUP 43.0gr H4895 – 2793 fps - 51,200 CUP 43.0gr IMR-4064 – 2726 fps – 48,100 CUP 44.0gr IMR-4064 – 2795 fps – 51,000 CUP 45.5gr W748 – 2731 fps Hodgdon service rifle load data, based on chamber pressure (Published in Hodgdon load guides numbers 25 and 26.) 150gr BT – military case 40.0-42.0gr H4895 – 2567-2735 fps (pre-1999 powder) 42.0-44.0gr H335 – 2589-2728 fps 45.0-47.0gr BLC2 - 2581 fps-2719 fps 150gr BT – Winchester case 41.0-43.0gr H4895 - 2694-2822 fps (pre-1999 powder) 43.0-45.0gr H335 - 2619-2806 fps (current max 44.0 grains) 47.0-49.0gr BLC2 - 2769 2878 fps (current max 48.0 grains) Note current H4895 was developed in Australia to replace the previous Scottish-made version in 1999 and use similar load data that had become popular over 20 years. They are not the same powders but load very similarly. HORNADY #7 .308 Service Rifle Data – based on gas port pressure in an M1A with standard unmodified gas system All loads are in Hornady/Frontier cases (same as Winchester cases) with Win WLR primers 150-155gr BT (2700 fps except as noted) Start 39.5 / Max 45.2gr - W748 Start 37.2 / Max 42.9gr – H4895 Start 37.6 / Max 43.4gr - IMR-4895 Start 37.6 / Max 43.2gr – Varget – 2600 fps Start 37.9 / Max 43.2gr - IMR-4064 Start 37.9 / Max 44.6gr – RL-15 Start 37.0 / Max 42.2gr – A2520 – 2600 fps Start 36.7 / Max 43.5gr - A2495 Winchester Load Guide In a Winchester case with a Winchester WLR primer 147gr FMJBT 45.2gr W748 - 2730 fps - 45,500 PSI The Winchester load guide data was developed at the time Winchester first switched to transducer pressure measurement instead of the copper crusher method. This load is milder than the factory 2800 fps load but was developed for using in the many old surplus rifles that were imported in the late 1980's and 1990's. If adjusting for case capacity, Winchester cases (and many Hornady Frontier brand) are about the only ones that might take a bit more powder. Many foreign-made cases are similar to military cases in capacity. Federal cases have similar capacity but are soft and thin in the case head with thicker case walls. Remington cases can vary quite a bit but are usually between military Winchester cases in capacity and are very soft. It's usually not worth loading higher for the small difference there might be. I recommend using military case loads for all cases except maybe Winchester commercial cases, but even then case life will be shortened. Changes in primer and case. (As tested by the NRA with 168 grain Sierra Match King bullets.) 38.5gr IMR-4895 – 2505 fps – 46,200 CUP 39.5gr IMR-4895 – 2565 fps – 49,100 CUP 40.5gr IMR-4895 – 2626 fps – 52,200 CUP With a 168gr SMK bullet and 40.5gr of IMR-4895 Change from Winchester to CCI-200 primer drops pressure 6,500 CUP and drops velocity by 45 fps Change from military LC case to Winchester case also drops pressure 6,500 CUP and velocity 45 fps Change in powder charge by 1.0gr changes velocity 60 fps and pressure 3,000 CUP |
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NATO Spec Per Wiki-
7.62 mm (7.62×51mm NATO) Service Pressure (Pmax) MPa / (psi) = 415.0 / (60,190) Pressure recorded in NATO design EPVAT Barrel with Kistler 6215 Transducer or by equipment to C.I.P. requirements An article on NATO cartridges lists the following: 60,191 psi (415.00 MPa) 147 gr (10 g) M80 FMJ 2,733 ft/s (833 m/s) 2,437 ft·lbf (3,304 J) Commercial/SAAMI- has charts for both CUP and PSI Win 308 Bullet 150gr MV 2800 FPS MAP (Max Allowable Pressure) 52,000 CUP (1 chart is CUP) 62,000 PSI (2nd in PSI) So, it appears that in this instance 52,000 CUP is approximately 62,000 PSI. And, the both the NATO and SAAMI Specs are close in velocity and pressure. The NATO spec AeroE posted listed is 50,000 PSI in the second reference, and it also indicated using a "Radial Copper Cylinder"... reading further it looks like this may be a CUP method which was once used as a pressure measurement. Also related to this subject, if you examine the Hodgdon load data tables for "308" you will notice some loads are in CUP and some in PSI- Max loads run about 50,000 CUP and about 62,000 PSI. I deleted non-pertinent load data- note the velocities are within range of each other. 2629 47,300 PSI 2819 59,600 PSI 2625 40,500 CUP 2793 50,200 CUP Conclusion: I think that the difference in the 2 measurement systems may have caused some confusion over the pressure specs for the 2 cartridges. Both NATO and SAAMI appear to be in close proximity for velocity and pressure- when the differences in the 2 pressure specs are taken into account. Military spec is for velocity at 78 feet, not at muzzle IIRC which could account for some difference. The biggest concern to a reloader/shooter of 308 and 7.62x51 appears to be the difference in case capacity and headspace between the two. Thanks guys, I learned a little more reading this thread and researching the above info. |
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FWIW- all my .308/7.62x51 loads are for M1A.
Arguably, IMR 4064 is the best powder for the M1A. My "everyday" plinking/blasting loads are 43.5 grs IMR 4064 behind Hornady 150gr fmj-bt regardless of case. I can tell a difference between Military (LC) and commercial cases with this load but am confident I'm not getting into pressure danger zone. I've used IMR 3031 for precision 165gr SST loads with success, have a bunch of H335 but won't burn it in M1A cause it's my AR's preferred powder. Tip: if loading for M1A, brass gets beat to death, I retire all brass after three reloads (4 firings total). Some M1A'ers don't believe in this, I take the point of view why take chances when brass is readily available? |
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NATO Spec Per Wiki- 7.62 mm (7.62×51mm NATO) Service Pressure (Pmax) MPa / (psi) = 415.0 / (60,190) Pressure recorded in NATO design EPVAT Barrel with Kistler 6215 Transducer or by equipment to C.I.P. requirements An article on NATO cartridges lists the following: 60,191 psi (415.00 MPa) 147 gr (10 g) M80 FMJ 2,733 ft/s (833 m/s) 2,437 ft·lbf (3,304 J) Commercial/SAAMI- has charts for both CUP and PSI Win 308 Bullet 150gr MV 2800 FPS MAP (Max Allowable Pressure) 52,000 CUP (1 chart is CUP) 62,000 PSI (2nd in PSI) So, it appears that in this instance 52,000 CUP is approximately 62,000 PSI. And, the both the NATO and SAAMI Specs are close in velocity and pressure. The NATO spec AeroE posted listed is 50,000 PSI in the second reference, and it also indicated using a "Radial Copper Cylinder"... reading further it looks like this may be a CUP method which was once used as a pressure measurement. Also related to this subject, if you examine the Hodgdon load data tables for "308" you will notice some loads are in CUP and some in PSI- Max loads run about 50,000 CUP and about 62,000 PSI. I deleted non-pertinent load data- note the velocities are within range of each other. 2629 47,300 PSI 2819 59,600 PSI 2625 40,500 CUP 2793 50,200 CUP Conclusion: I think that the difference in the 2 measurement systems may have caused some confusion over the pressure specs for the 2 cartridges. Both NATO and SAAMI appear to be in close proximity for velocity and pressure- when the differences in the 2 pressure specs are taken into account. Military spec is for velocity at 78 feet, not at muzzle IIRC which could account for some difference. The biggest concern to a reloader/shooter of 308 and 7.62x51 appears to be the difference in case capacity and headspace between the two. Thanks guys, I learned a little more reading this thread and researching the above info. Correct, also note that the NATO Allies place the CIP measuring system sets the sample point further forward in the case, so it sees a bit of the pressure drop at the bullet base that occurs when the bullet starts moving. That makes them tend to read about 2,000 psi lower than the SAAMI setup does in this pressure range. So the same ammo would measure closer to 62,000 psi in SAAMI equipment. |
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On the topic of whether CUP is "pressure". CUP means Copper Units of Pressure. This method requires calibrating a lot of copper cylinders called "crushers" under a hydraulic cylinder to calibrate the crushers to the applied pressure which is correlated to chamber pressures. It is indeed a measure of pressure, in the same sense that using a piezo element or even the measurement of temperature in a vessel can be used to infer pressure, which is what every instrument that measures pressure does. There is a difference in just what the crusher and piezo methods measure. The piezo method measures the time history of the pressure, so the true peak pressure and its dwell time can be measured. The crusher method does not measure the peak pressure, what we really get from this method is the total energy applied to the crusher, hence the reason the magnitudes appear to be lower than the peizo method. The energy from the chamber pressure is the same. There is no accurate conversion between the two methods. |
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Headspace is weapon specific. A lot of internet sources like to quote the original 1950's M14 headspace specs as being the universal headspace for military 7.62x51. This is not accurate. The original M14 headspace was made the same as the belt fed M60 machine gun and used the same headspace gauges. The FN FAL, H&K G3, Beretta BM59 and the Armalite AR10 all have different headspace specs. The match and sniper versions of the M14 have tighter headspace specs. The newer, "special purpose" versions of the M14 have even tighter headspace specs.
The SAAMI headspace specs call for a range of 1.630" to 1.640". There is only a minimum and a maximum. There are no SAAMI specs for, "Go", "No-Go" and "Field" headspace specs. Those are spec'd by the individual tool and gauge companies and are not always the same from each company. For many SAAMI rifle cartridges the headspace range is 0.010". Many tool gauge companies use the minimum for their, "Go" gauges and cut the difference to maximum in half for their, "No-Go" gauges. For many popular match and target (and some hunting) cartridges some tool and gauge companies subtract an additional 0.001" in an effort to improve accuracy and / or case life. Then this 0.004" difference is doubled for their, "Field" gauges. The US military buys headspace gauges for the FN-made M240 belt fed machine gun from FN and they are only for use in the M240 as it has its own unique headspace specs. The biggest difference in 7.62x51 chambers and SAAMI 308 Winchester chambers is the throat. This also happens to be the biggest difference between 5.56x45 chambers and SAAMI 223 Remington chambers. The chamber throat often has more of an effect on chamber pressure than headspace. A short, tight SAAMI throat can be relieved a bit by increasing headspace a bit, but additional headspace usually won't change pressures as much a different chamber throat does. Of NATO certified 7.62x51 ball ammunition their are three main bullet designs used. The first design is the NATO reference cartridge that uses a bullet that has a nominal weight of 146 grains. The next design is the FN SS77 which has a nominal bullet weight of 144 grains. US military originally used the steel core M59 cartridge, for political reasons, and it was made by both Winchester and Remington. Winchester was involved in designing the cartridge and Remington was owned by Dupont which had huge influence, so it was decided to split production between the two. The M59 bullet was made in two designs. One had a cut cannelure and the other had a knurled cannelure. The bullet weight specs were a maximum of 150.5 grains (to minus 6.5 grains for the cut cannelure and to minus 5.5 grains for the knurled cannelure). The military wanted a lead core bullet but a steel core bullet was originally used for political reasons. The lead core bullet M80 cartridge was developed at the same time under the guise of being an overhead live fire training cartridge. The M80 cartridge started replacing the M59 cartridge in 1966. The M80 cartridge was not NATO certified until August of 1967. The bullet weight of of the M80 bullet is 149 grains maximum (to minus 3 grains). Of the three NATO certified bullets, the FN SS77 has the longest bullets and the lightest. The NATO reference bullet is shorter than the FN SS77 but longer than the US M80 and also is slightly lighter in weight than the M80 bullet. The US M80 bullet is the heaviest but has the shortest length. There are no NATO specs for heavier bullets. The measured chamber pressures of the M118 and M852 cartridges by the NRA were both higher than the measured M80 cartridge chamber pressure. The original specs for the M118 Long Range cartridge called for SAAMI pressure limits but not using a SAAMI spec chamber. The bulk Winchester 147 grain bullets have given me fairly poor accuracy. Pulled M80 bullets have been better in accuracy but not great. The, "Mil Spec" brand / Serbian Prvi brand 145 grain bullets aren't bad for accuracy. (The heavier, "match" bullets by the same maker seem worse.) The 150 grain Sierra and Hornady bullets have given me very good accuracy,. They are nearly the same design except for the location of the cannelures. Loading to the Hornady cannelure results in a shorter cartridge length. The Speer version isn't bad. When on sale they seem like an alright deal and they are usually better than cheaper bullets. |
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Most foreign-made cases are near Lake City case capacity. Some Lapua cases have very slightly larger capacity than LC cases. Federal commercial cases have the same or even slightly less case capacity than LC cases and are softer and weaker. Nosler cases are the same as Federal cases. Remington cases usually have slightly more capacity but are very soft and weaker. The Remington case capacity is less than Winchester commercial cases, Winchester cases have the largest capacity and might be the only ones with enough difference and strength to allow a powder charge increase adjustment. Note that 50 feet per second won't make a trajectory difference outside of the accuracy of the cartridge. Hornady and Hornady brand cases are usually the same as Winchester cases. There are a few that are slightly heavier but generally Hornady, Frontier and Black Hills cases are Winchester cases and Nosler cases are Federal cases.
Some pressure and velocity differences with charges components. Difference between mild primer and hot magnum primer - 6,500 CUP and 45 fps Difference between Lake City case and Winchester - 6,500 CUP and 45 fps. Difference in one grain powder charge change with IMR-4895 - 3,000 CUP and 60 fps. From the above data it can be seen that the cases with the largest capacity difference have less than 50 fps difference in velocity with all other components remaining the same. Note this used loads developed in Lake City cases, so the pressure would drop in Winchester cases. If a load is max'd out in Winchester cases, the pressure increase would be about the same amount but might exceed the desired maximum pressure. In theory a change in both case capacity and primer type could result in a change in pressure of 13,000 CUP and a change in velocity of 90 fps. This would require a change in powder charge of 1.5 grains for exactly equal velocity but keep[ in mind that a 50 fps change in velocity won't be noticeable in trajectory. 1.5 grains of powder in this example would change pressure by 9,000 CUP. This data was developed with 168 grain bullets but the earlier posted data with 150 grain bullets can be compared for powder charge changes. A bigger issue than velocity change is accuracy change. A change in components can change accuracy enough to make a small change in components create a large change in accuracy. |
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