the ogive on a 175g Partition (new to reloading)...

[TNBillyEarl]

I just started reloading, 7mm RM. I was making all my cartridges 3.290 inches, but could not get consistent groups (sub MOA) with 175 Partitions. Accubonds, yes. 140g Partitions, yes. So I bought an OAL gauge and started measuring the ogive. It appears to me that the ogive on 175g Partitions is higher up on the bullet. The picture above shows my measurements. If I go .02" off the lands with 175g Partitions then my length on these is to be 3.260, even though the OACL by SAAMI is 3.290.

Am I off on this? Please advise...

-B

 

[ShadeTree]

No, you're not off. Provided you took correct measurements. It happens. Some chambers are short throated, some bullets hit the lands at a shorter OAL. Nosler is showing they tested at 3.290. Why? Because their chamber would allow it. Yours will also but it pays to know ahead of time you will be jammed into the lands which increases pressure and IMO is not optimal for hunting.

Saami length on a 30-06 is 3.340. I got one here that every bullet type of every weight I ever checked wont allow me to get anywhere close that. Most are into the lands somewhere around 3.250, some less than that. You will find that most factory ammo in whatever cartridge it's in, is usually loaded well below max saami length.

 

[mjcmichigan]

You’re correct to check the ogive and distance to lands.

Great you’ve got the AccuBond grouping. Great bullet, and sometimes it matters a lot how deep you load AB.

Back to the partitions, if your magazine can handle that OAL, definitely try different seating depths. 0.02”-0.05” works for many cup and core bullets.( lead wrapped in a jacket). Bonded bullets and monos often like a lot of jump.

Check your magazine length,and if the partitions fir when seated 0.02” off the lands try it. I’d guess the magic location will be between your first oal, and this one you’re about to try.

I start with book oal or 0.02” off the lands.


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[mjcmichigan]

I’ll double the short throat comment.

I have two with short throats. Annoying at times. I just measure first before loading SAAMI.


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[gbflyer]

7mm RM breathes enough fire that it won’t be short for long.

 

[TNBillyEarl]

Many thanks for the replies/information. I know so little; but lurking here for a few months has definitely increased my learning curve. Taking the 175g Partitions .015 off the land measure I got this:



That's 63.0g of RL-22

-B

 

[mjcmichigan]

Looks like you are off great start!

The the ole 7mm singing with several bullets and quickly.

What’s the rifle?
Optics?


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[TNBillyEarl]

Quickly? This has not seemed quick at all. (But I have enjoyed the process. I should have started this years ago.)

Last year I bought a 2003 Rem700 at an estate sale. First bedding job. First free floating job. New trigger and butt pad. I have always hunted woods until this year when invited out to Oklahoma. That required practicing at over 100 yards, and of course a little more rifle. Added a DNZ one piece and a Burris FF2 3-9x40.

Any grouping under 1 MOA is functional accuracy for my hunting. My preferred bullet is the Partition so that is what I want to develop around. I have never shot Accubonds until last month. But if Partitions are functionally accurate inside 400 yards - which they are - I can't see myself shooting anything else.

Again, thanks to all of those who post answers in the different threads on this board. It has greatly helped me.

-B

 

[mjcmichigan]

Recommend you consider the range you zero your gun.

My 3006 is 1.3” high at 100 And dead on at 200. This means 0-230 yards I can aim dead on and be never more than 1.5” high and 1.5” low. 6” hold over at 300, and something like 18” at 400.

Helped a friend with a 30-378 and with that cartridge, we zeroed at 300. It’s tunnel is similar just out an extra hundred in each drop. (30-378 is a powder hog, 120gn of powder to fill the case vs 60 in a 3006 or 70 in a WSM, and 80 in a WM)

With that 7mm and a 175, you can probably choose between 200 or 300 zero and have a similarly narrow tunnel to cover 75% of the yardages you’ll be shooting!

Looks like your gun smithing paid off nicely!


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[Joec7651]

3.290” coal with 160gr PT’s would put me .050” into the rifling in one of my 7mm RM’s and .040” into the rifling in the other. Adjust your coal to fit your chamber and throat with which ever bullet you load. I start at .020” off the lands and work up to the most accurate charge weight. Then play with seating depth to tighten the group from there.

 

[seokladuckin]

Many thanks for the replies/information. I know so little; but lurking here for a few months has definitely increased my learning curve. Taking the 175g Partitions .015 off the land measure I got this:



That's 63.0g of RL-22

-B

Both my 7 mags love RL-22

140 ballistic tips, 63.5 grains

One shot .226 , one .328, bone stock factory rifles with trigger change, one is a 1980 700

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[JD338]

Nice work! The sweet spot for most PTs is .015-.020" off the lands. If you try seating a little deeper, you just might tighten up your group even more.
Another option might want to consider is the 160 gr PT. It would give you a little more velocity and flatter trajectory. Penetration is excellent.
Also, consider the 168 gr ABLR. Excellent long range bullet.
Welcome to the forum, glad you are here.

JD338

 

[SJB358]

Great shooting, the old 7 Rem hardly ever fails to impress. The 175 PT or anything Nosler makes is really a darned good deer and elk rifle. Looks like you're doing real well. That 175 Partition has been excellent for us on elk as well. Not much more you could ask for.

 

[Guy Miner]

Completely agree with Scotty - the long & lethal 7mm 175 Nosler Partition is a pretty doggone terrific hunting bullet. I've only taken one elk with it - but very good bullet performance! And it's accurate in standard twist 7mm Remington Magnum barrels as well.

No flies on the 160 gr versions either - and it's easier to get them up to 3,000 fps or a bit more. Last fall I used a remarkably accurate load with Sierra's 160 gr SPBT Gameking & RL-22, at 3050 fps for mule deer & antelope. Bullet performance was very good.

TNBillyEarl - have you used the Partitions on game before? The front portion tends to expand very quickly, causing much damage. Then that rear shank continues to penetrate, often exiting. Many times the exit holes are smallish - because the front "mushroom" has already been shed, inside the animal. That's never been a problem for me though - the internal damage has been quite sufficient to produce very quick kills.

BTW, loaded well, the Partition can be very accurate... I think you'll like your results.

Regards, Guy

 

[SJB358]

Completely agree with Scotty - the long & lethal 7mm 175 Nosler Partition is a pretty doggone terrific hunting bullet. I've only taken one elk with it - but very good bullet performance! And it's accurate in standard twist 7mm Remington Magnum barrels as well.

No flies on the 160 gr versions either - and it's easier to get them up to 3,000 fps or a bit more. Last fall I used a remarkably accurate load with Sierra's 160 gr SPBT Gameking & RL-22, at 3050 fps for mule deer & antelope. Bullet performance was very good.

TNBillyEarl - have you used the Partitions on game before? The front portion tends to expand very quickly, causing much damage. Then that rear shank continues to penetrate, often exiting. Many times the exit holes are smallish - because the front "mushroom" has already been shed, inside the animal. That's never been a problem for me though - the internal damage has been quite sufficient to produce very quick kills.

BTW, loaded well, the Partition can be very accurate... I think you'll like your results.

Regards, Guy

Yeah, I'd agree, the exits aren't usually huge, but I've never taken a deer or elk with one and wished for too much different results. I had a cow run 50-60 yards in the timber once, but the shot was a bit high in the lungs, I suspect it just took a few seconds for her to succumb. The 175 is pretty well shaped for a flat base bullet as well. Hitting out to 600 or more has never been an issue in my Mashburn.

 

[TNBillyEarl]

All, many thanks for your advice and information. Since measuring to the ogive I have gotten consistent groups week to week with both my 175g and 160g Partitions. Now to get to work on my 7mm-08.

Bill

 

[TNBillyEarl]

Update - For the last 3 weekends I have gotten .7" for each 3-shot group with 175g Partitions, and .5" for 160g Accubonds. (I have been so pleased with this.) I picked up a headspace gauge last week to make my brass more consistent; and then I seated the Accubonds a few thou lower b/c of a recommendation from a post on this forum. I hit pay dirt. The group below is at 200 yards, over 3000 ft/sec, and a .18 MOA. The weekend before my group was similar but only at 100 yards.

To think I was thrilled with .5" -- now this...



Many thanks to you all. I think I'm going to stay with the Accubonds. And should anyone care - this is what I have settled on:

63.1g RL-22
160g AB
2.120" for headspace on my 700 7mmRM
2.7485" base to ogive for seating depth
RP brass, Fed Mag Primers

 

[ShadeTree]

That's excellent! You are to be congratulated. Good work! It's a bug. Accurate rifle's and good reloading techniques will only make the bug worse.

 

[DrMike]

Always a positive experience when you find the sweet spot. Congratulations on an excellent load.

 

[Guy Miner]

Excellent!