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| One of Us |
How does one decide that a certain f.p.s. is fast enough (or not fast enough) for a specific caliber? For example, I shoot a 7mm Rem Mag and I'm unsure as to what speed I should be "aiming" for. I'm loading 168 Matchkings over 69.2 grains of Retumbo and it is going to be used for ringing gongs at 600 yds or less. What speed should be the minimum? Thanks. | ||
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I would not chase velocity. I would chase accuracy. With a 300 yd zero, the difference in drop between a MV of 2800 vs 2900 for your selected bullet is about 5 inches. Once you determine what your zero range is going to be assuming you aren't going to zero at 600, the difference in hold adjustment for 100 fps difference in MV is not going to be the issue. Trying to find a 1/2 MOA load versus a 1 MOA load will be. The military 308 173 grn sniper round is easily effective to 600 meters and it has a muzzle velocity of 2650 fps The 50 BMG 750 grn round round is easily effective to 1000 meters and it has a muzzle velocity of about 2700 fps Mike Never under estimate the internet community to use any opportunity to reply to a post with their personal rant about their tangentially related, single occurrence problem.  What I have learned on AR, since 2001: 1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken. 2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps. 3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges. 4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down. 5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine. 6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle. 7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions. 8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA. 9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not. 10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact. 11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores. 12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence. 13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances. | |||
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 nailed it!/////////////////////////////////////////////////////////////////////////// "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery." Winston Churchill | |||
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| one of us |
The rifle will tell where the accurate velocity node is. My 7mmRemMag was most accurate with 168s at a little over 3000fps. | |||
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Mike is quite correct. Even the 147 gr. NATO 7.62 (.308 Win) ball round is effective in shooting at a 12" bullseye at 1,000 yards in DCRA fullbore competition, with iron sights. So, at a set, known, medium distance like 600 yards, accuracy is what you need, not improved ballistics. | |||
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Accuracy is the primary objective. Velocity can be your friend if you are shooting at longer distances and where either "holdover" is involved or clicks on the scope. A lazer range finder will help in knowing the distance, but if one is not handy or quick enough in the situation a flat shooting round will reduce a lot of misses due to incorrect range estimation. This is more applicable at the long end of the shooting spectrum but then again hitting things at long distances is hard to begin with. I like accuracy first and then experiment with velocity watching for deterioration in the accuracy. A great combo = accuracy and velocity!!! | |||
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| One of Us |
And I would add that you want to match the velocity to the bullet if hunting. Lots of FPS with an accurate load isn't very useful for hunting if the bullet will vaporize at the likely impact velocity. But you also need enough velocity to expand the bullet too if it's a harder one. But if target shooting only, velocity is a very much secondary consideration. LWD | |||
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We don't know either, it's a personal choice, not a group thing. Personally, I develop loads for accuracy but only at or very near book maximums. If a powder won't give me good accuracy at top speed I try another powder. Not much value in a 7 mag if it's loaded to 7x57 speeds is there? | |||
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I always begin with a new rifle or load by looking to see where the Pressure is at a SAFE MAX with a Match Grade Bullet Seated 0.010" Into-the-Lands using good old, CHE & PRE. Once I know where the SAFE MAX is located, then I run the never improved upon Creighton Audette Load Development Method to locate the best Harmonic Node that is closest to the SAFE MAX Load level. However, you question is not necessarily that simple. The core problem lies in how many shots you can shoot, at any specific velocity level, with a specific weight bullet, and remain focused on your shooting form without going into a case of the uncontrolable Flinches(or as we colloquially refer to it on the Board as the "slamfires or teenScums" in dis-honor of those two fools.  .You will want the most Velocity you can handle because the Time-of-Flight to the Gong will be reduced which means the Wind has less opportunity to affect the Bullet's Flight Path. On the other hand, reducing the Velocity will reduce the Recoil(the dreaded jeffee Syndrom), and that will allow more clean shots while able to maintain a proper focus on your shooting form. So, I'd say Jim C. is right on the nose - only you can decide what it should be for you. By the way, there are "lighter" Match Grade Bullets available in 0.284". But there is certainly nothing wrong with the one you selected. Best of luck to you. | |||
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Regarding recoil...I can literally shoot a 7 mag all day. For whatever reason I love that caliber. It's not loaded terribly hot but sure is accurate. | |||
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To a point this is true, but I would not want to buy a 7RM to shoot 7-08 vel. There is a balance in all cartidges of vel/accuracy. If all I could get was 2700fps w/ 168grSMK in my 7RM, I would probably sell it & buy a 280. The actual vel to shoot a target @ known distance is kind of irrelavent, as long as you know what that vel is, especially out to 600yds, as Mike noted. LIFE IS NOT A SPECTATOR'S SPORT! | |||
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The Sierra manual will give you an idea of a "performance range", i.e. a starting load and a max load with several powders for that bullet. Pick a suitable powder (4350 works well). Then, to ring gongs at 600 yards, work up a load within that range. The chronograph will tell you the consistency of the internal ballistics. The target group will tell you the accuracy potential. Use both to find the load. As mentioned, do not just chase velocity. Accuracy on target at 100 yards (the usual test range) may not tell you what the load will really do at 600 yards. Conversely a load with that bullet that has consistently low ES/SD and groups well at 100 yards will also do well at 600 yards. Larry Gibson | |||
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