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Thread: 375 260gr Partition question

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    Default 375 260gr Partition question

    Does anyone have any 260gr partitions on hand? I am trying to figure the seating depth from the base of the bullet to the crimp canalure. I am building my wife a carbine for us to take to Alaska but need to know if my cartridge oal will work with this bullet. Thanks for help in advance.

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    Member alaska bush man's Avatar
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    Question 260gr

    The Nosler 260gr Part is a good bullet but I suggest the new 260gr Nosler Accubond.

    What cal are you going to load .......375HH .....375 Ruger etc before I can answer your COL question?
    Alaska

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    .375 carbine..man your wife is tough

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    I have some loaded 260 and 300 grain partitions and they measure 3.600". In brass that is no longer than 2.850" the overall length will be 3.600" into the middle of the cannellure. 3.6" is the max COAL of the 375 H&H and just about everybody who makes bullets for it with a crimp groove or cannellure will have it placed to make the 3.6" overall length.

    I really like the 260 partition in the old H&H. It makes a very nice light load bullet and can be loaded from 2600 to 2800 fps and will handle just about everything but cape buffalo and the biggest bears very well. I've taken everything from mice to moose with it and it has always served well. I've made some very long shots with that combo also. Well, long for the H&H or maybe just long for me, over 300 yards.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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    Very good shooting bullet in the H&H. I seem to recall with brass trimmed to SAAMI min. my O.A.L. being 3.575-3.585

    My H&H's seem to prefer them with a stiff charge of RL15. Very easy to get 2750 in a 24" barrel.

    I can get you some base to cannelure measements when I get back to my bench.

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    I'm loading it in a model 7 300 SAUM necked up to 375 for the wife. She shoots the 416 Taylor with 400gr at 2400 but doesn't like the weight of the rifle. Her model 7 in 300 SAUM with 180 at 3000fps is her favorite rifle and I am building this one to give her more bullet weight and frontal area for use on bears. Have the utmost faith in partitions which is why I wanted to go with the 260gr as my OAL can not exceed 2.8in in the model 7, the 300 grain would extend into the cartridge powder column. Thanks for the replies guys, as I am out of state and have no access to my reloading comp.

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    3.600 is the max case length. The 260 partition is a great lighter load, however when pushing a bullet at 2700-2800 fps, you don't get the optimal longer range performance due to it's low BC. The new 260 accubond loaded at 2800 fps will yield nearly 2400 footpounds at 400 yards. And shoot as flat as a 150 grain 270.

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    Member alaska bush man's Avatar
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    Thumbs up Reloader 15/260gr AB

    Same here with RL 15 and 375HH or 375 Ruger switched over from the 260gr Part to the 260gr Accubond with high BC.......sure shoots sweet.

    So that is a custom 375 SAUM I suggest the same length as the 300 SAUM or at least to the crimping grove on the AB bullet.

    Trying to inform you Paratropper the 260gr Nosler AB has a higher BC! I use it in 375 Ruger Alaskan.......sweet!

    Instead of building a rifle, just buy her a Ruger Hawkeye Alaskan 375 Ruger and have it Mag-Na-Ported!
    Alaska

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    AK Bush Man and IdahoTrophyHunter, I know a lot of folks are pretty happy with the AB bullets and the Swift Sirocco also. I don't know anyone who has actually used these bullets and encountered heavy bone. I have used the Partitions for all of my bear and deer taken, and have seen them hold together through heavy bone. The lower velocity this wildcat would produce would be helped by the higher BC no doubt but she rarely takes shots more than 100yrds as part of our enjoyment is the stalk and we like it close, (my reasoning for more bullet weight and frontal area). I am sure the 300saum with the 180gr Partitions would do her just fine in 99% of the circumstances but that 1% in bear country is a lot of comfort. I plan for us to hunt the Brownies at least once and consider 338win mag minimum for them. The wife shoots the 375 h&H better than the 338win saying the 338 slaps her more than pushes. She even prefers the 416 Taylor to the 338. She is small framed and the model 7 fits her so perfectly and naturally she is found of this rifle and very familiar with it which are huge benefits to my mind. Thanks again guy for the replies.

    TomM thanks for taking the time to shoot the measurements to me. I should have the barrel in at the end of the month. You really help me out as I mentioned the project was stalled out until I could get those figure in.

    Best to all

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    No problem, glad I could help. Good luck on your hunt.

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    Any recipes that your willing to share on loads for the Nosler Partition and Accubond bullets for a Ruger .375 Alaskan?

    I'm planning on a Moose hunt and perhaps a Brown with my brother this fall. I'm shooting the gun this weekend for the first time with factory ammo and looking forward to loading up some 260's.

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    [QUOTE=marshall;255992]Any recipes that your willing to share on loads for the Nosler Partition and Accubond bullets for a Ruger .375 Alaskan?

    Like "Alaska Bush Man" I'm using RL15 with good results in my 375 Ruger Alaskan.
    I've settled on 75.5 gr with the 260 Accubond for now - less than 1" groups at 100 yds and zeroed at 250.
    Bob

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    Thanks BobG:

    I was thinking the same thing about the 250 yard zero.

    Initial calculations show +3" at 100 yards and a -4" at 300 yards. Are you finding that to be about right?

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    Quote Originally Posted by marshall View Post
    Thanks BobG:

    I was thinking the same thing about the 250 yard zero.

    Initial calculations show +3" at 100 yards and a -4" at 300 yards. Are you finding that to be about right?
    Hi Marshall,

    Actually I'm about 3 1/2" high at 100 for the 250 yard zero with the 260 Accubond.

    Cheers, Bob

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    Quote Originally Posted by BobG View Post
    Hi Marshall,

    Actually I'm about 3 1/2" high at 100 for the 250 yard zero with the 260 Accubond.

    Cheers, Bob

    How many inches at M.O., six?
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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    Quote Originally Posted by paratrooper4life View Post
    Does anyone have any 260gr partitions on hand? I am trying to figure the seating depth from the base of the bullet to the crimp canalure. I am building my wife a carbine for us to take to Alaska but need to know if my cartridge oal will work with this bullet. Thanks for help in advance.
    I have figured out what you are wanting now but I think you need the length of the nose to add to the case length for you max over all in the 300 RSAUM/375. I haven't seen that one did you dig that up yourself? You are rebarreling the RSAUM, right?
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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    Quote Originally Posted by Murphy View Post
    How many inches at M.O., six?
    Hi Murphy,

    4" if I understand what M.O. is.

    Bob

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    Quote Originally Posted by BobG View Post
    Hi Murphy,

    4" if I understand what M.O. is.

    Bob
    http://www.snipercountry.com/Articles/MilDot_MOA.asp

    If your talking about (MOA) then your getting better than 1" based on your previous post. That would be better than a 3" group at 300 yards. The above link has a good explanation, sorry if I'm keying in on the wrong subject.

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    Quote Originally Posted by marshall View Post
    http://www.snipercountry.com/Articles/MilDot_MOA.asp

    If your talking about (MOA) then your getting better than 1" based on your previous post. That would be better than a 3" group at 300 yards. The above link has a good explanation, sorry if I'm keying in on the wrong subject.

    I'm talking about M.O. Maximum Ordinate. The highest point above the line of sight in the trajectory of a bullets travel. It is not at 100 yards, it is not at the mid range of zero point it is somewhere between mid range and zero range. You folks talk about sighting in for this or that at 100 yards, do you know what lies in between?
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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    Quote Originally Posted by BobG View Post
    Hi Murphy,

    4" if I understand what M.O. is.

    Bob
    That is a common misconception. M.O. Maximum Ordinate-The highest point of a bullets travel above the line of sight (LOS) in the trajectory.

    If a bullet is zeroed at 250 yards it will be some distance above LOS at 100 yards. It will be some distance above at the 125 yard point (mid range) and it will cross the LOS (for the second time at the zero range.

    The trajectory of a bullet is such that the highest point (M.O.) is about 2/3rds of the zero range, depending on flight time. Bullet drop is a constant function of gravity per unit time (32.14 ft per second). The slower bullets spend more time and drop more, faster bullets drop less.

    Velocity decays at a rate based on the BC of the bullet. The rate of velocity decay is a logrithmic function (natural log, e), so downrange the velocity decay is greater. In other words it is not a linear function. If it were, at the mid point of the zero range, the velocity drop would be half what it is at the zero range. That isn't the case.

    If the trajectory of a bullet is +3"at 100 and its zero is 250 yards, the mid range is about 4.5 and the M.O. is maybe 5 to 5.5" then it bigins to drop quickly.

    If you have a ballistics program you can play with numbers and see how it turns out. I think some of these calculators are on line. You need the velocity and true BC numbers for these to be effective.

    The important part of this for hunters is that when 3" high at 100, you could be so high at about 175 yards to cause a miss or high hit especially if you over estimate range and hold higher on the animal. 250 and 300 yard zeros are not a good idea with calibers with the flight time of the 375 H&H and even more critical for the slower wildcats of the 375 bore.


    We all need to shoot more at known ranges to see the real field trajectory of our rifles.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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