What first? Powder or seating depth?

[Chris89lx]

Finally have most pieces together to start reloading for my7MM Rem Mag.
Its a model 700 SPS with detachable magazine.

I'm loading 168 Berger hunting VLD's with RL-22 powder and Federal 215 primers. It's going into once fired Federal brass.

Here is the load data Berger sent me.

Load data was generated using Quick Load a 26 inch barrel a COAL (cartridge over all length) of 3.290 inches and your COAL and velocity could be a little different.
Bullet------Powder-----Start Load--Approximate Start Velocity---MAX LOAD--Approximate Max Velocity -----Fill Ratio
168 Grain--RE-22---------58.5---------2701----------------------65.0----------2984-----------------------96.2%


Here is were I am thinking of starting...

As long as the recomended 3.290 COAL fits into my magazine. I will use that as a COAL to start building up a load for my rifle.

Then if I want more acuracy out of it after that. I will start adjusting seating depth.

Am I going about this the correct way??
Any other recomendations?

[ChubbS]

3.29 oal is pretty common and should fit ANY 7mm rem mag chamber/mag. I would find a load that shoots under an inch at 100 or better at 3.29 oal, (in the low end of your powder range) then start seating bullets out further while watching for signs of pressure(seating the bullets out further can actually increase pressure). Once you've found a good OAL then you can slowly work up the charge to maximize velocity(watching for signs of pressure of course).

this is how i do it and has worked for me

in my 7mm rm i use retumbo powder and accubond bullets with cci primers, and my gun actually shoots best at 3.29 oal

[elkhunter11]

If the magazine allows, I start with conventional bullets .010" off of the lands, and monometal bullets .050" off of the lands. A COL posted in a loading manual really doesn't mean much for your rifle, due to variances in throat lengths, and variances in bullet shapes. I try different powders to find a load that shows potential, and then I work up the powder charge. The last thing that I do is to fine tune the seating depth.

[Mad_Mikee]

I usually start with powder and then work on OAL.

What I usually do is start from the median load and increase powder in 0.5grain incriments until I hit max load.

ie. If the min load is 40 and the max load is 50 grains, I'll start at 45 and go up to 50 (45, 45.5, 46, 46.5, ...).

As for OAL (if the mag box or magazine allows), I find the point where the bullet jams into the lands but the bolt will still close. Then I seat the bullet usually 0.010 deeper.

Once I find the best powder charge, I'll head out to the range and try that same load again but at different lengths off the lands (jammed, 0.010, 0.020, 0.030, 0.040 and 0.050).

This system has worked for me at least.

[tchardy1972]

I find the hardest thing in load development is deciding what powder to use. When I do decide, In a case that big I will load in 1 grain increments with the bullet .005 jump. When i find what charge shoots best I load that one again and .5 of a grain on either side and with a bigger test sample. I pick the load that shoots best then adjust the seating depth in .010 at a time. If time allows there is always tuning that could be done to powder charge and seating depths later in smaller increments.
The problem with starting at the recomended seating depth is you don't know which way to go. If you start close to the rifling there is only one direction to go.

[Lefty-Canuck]

When choosing a powder I usually look what I have on my shelf, then cross reference my books to see if they will work for the cartridge I am loading for. Then I choose the powder that offers the highest velocity.

On my shelf I have,

H4831
IMR4831
Varget
RL22
IMR7828 SSC
IMR4350
H322
WIN760

If I can't find a decent load with these....I sell the rifle.

LC

[omega50]

I try to make sure all of my brass came out of my rifle so that it has been fire formed so that I can neck size.

If not then I full length size and trim.

I try to eliminate as many of the variables as possible to reduce frustration and achieve my desired outcome.
Keep good records of what you have done. Keep load development to small samples til you have it where you want it.

It was all sooo much easier when I could only afford 1 type of powder(Reloder 22). I was forced to work the loads with powder grain changes and seating depth changes ( lots of throat erosion in my old 7 rem mag ) without prematurely chasing other powders.Rounds that gave me great accuracy would not even cycle in my friend's rifle.
I used to find factory loads that shot halfway decent and then pull the bullets and weigh and try to identify powders.
In the end for me-The sun even shines on a skunk's ass sometimes-and I got lucky

Great advice from tchardy1972 about seating depth.

[LongDraw]

Learn how to measure where the bullet you have chosen engages the rifling in your gun. A bullets length can vary up to .010". Measuring off of a bullets ogive is more consistent way to measure, you will eliminate the differences in the bullet length above the ogive, where most of the difference in bullet length is. Using COAL includes this difference in bullet length. Do a search on this, many different methods and tools to measure where your bullet engages the rifling.

Here is a good article written by Berger that discusses seating depth, jump, jam, and how to look for accuracy varying seating depth with VLD's;

http://02b0516.netsolhost.com/blog1/?m=200904

[Chris89lx]

Finally had a chance to experiment with an OAL that fits in my magazine.

Made up a dummy round and found that a 3.400" OAL fits in my magazine nicely with a little clearance and cycles through the gun just fine. (3.290" is book spec)

After that I wanted to know how far off the rifling the bullit was sitting.

I dropped a bullit into the chamber but when I tipped the barrol up the bullit would fall out. I dropped it in again and with a very light tap of the barrol on the carpeted floor. The bullit was stuck and would not fall out when I tipped the barrol up.
Then I used the rod from my cleaning kit and ran it up the barrol ever so slowly until I felt it touch the tip of the bullit. I then put a score mark with a utility knife blade on the rod. After that a slight tap with the rod and the bullit came out.
I then chambered in my dummy round. I took my cleaning rod again and slid it into the barrol untill it touched the tip of the dummy round. I once again scored a mark on the rod at the end of the barrol with a utility knife blade.

I know this method is not the most acurate for measuring this but I think it worked pretty good.
The measurement between the two score marks was approx .060"

I'm not sure if I will even play with the seating depth. But a least I know approximitly were it is.
Time to start loading and testing.

Thanks for the great info everyone.

[densa44]

I'd start with the way Elk does it and if that doesn't suit you, pick another reply, they are all good.

For me I never tinkered with the length (not on purpose) but I did pick my favorite IMR powder and just move it up .5 gr at a time. The 6.5 and 06 just love it.

[catnthehat]

With my match rifles and hunting rifles alike, OAL first to get the accuracy , then I mess with the powder to get the velocity.
Then both get tweaked if a compromise is needed on the hunting rounds.
Cat

[260 Rem]

I start with the bullet I choose .007 to .010 off the lands and work on powder in 0.5 grn increments from a couple grs under max to max...then take the best potential and tinker with seating depth. For paper shooters, I disregard magazine length as they will be single fed. I sometimes exceed mag length in a hunting rifle for "sit and wait" applications where I will chamber a round and sit with the safety on....and load a second "long round" in the mag as it will generally still sit under the closed bolt.

[Chris89lx]

It crossed my mind to disregard the magazine max length and feed single rounds. Would this not change POI if everything else remains the same?
Could everything remain the same? Would there not be possible higher pressures seated closer to the lands?

[catnthehat]

Would there not be possible higher pressures seated closer to the lands?

Yes, the closer to the lands, the higher the pressure, which at times is not a bad thing, depending on the powdr being used.
Cat

[Sneeze]

My 2 cents is you will probably find the OAL a variable you can not play with.

Your magazine length is going to be significantly shorter than your optimal OAL.
The best starting point is an OAL that fits properly in your magazine and cycles easily with out snagging bullets.

The battle will be getting the bullets as long as possible before you have cycling problems.

Have fun reloading!

[catnthehat]

My 2 cents is you will probably find the OAL a variable you can not play with.

Your magazine length is going to be significantly shorter than your optimal OAL.
The best starting point is an OAL that fits properly in your magazine and cycles easily with out snagging bullets.

The battle will be getting the bullets as long as possible before you have cycling problems.

Have fun reloading!

Not all magazines have a limted length, one does have to be aware of it however.
Some bullets such as the barnes work very well far of the lands, as well.
those of us who shoot single shot rifles do not have that worry, of course!:sHa_shakeshout:
Cat

[260 Rem]

It crossed my mind to disregard the magazine max length and feed single rounds. Would this not change POI if everything else remains the same?
Could everything remain the same? Would there not be possible higher pressures seated closer to the lands?

In most rifles with magazines, it is possible to put a single round in the magazine that fits under the closed bolt. The bullet tip fits into the feed ramp. If I am waiting on a hill, using long seated bullets, I hand feed one into the chamber, and then put one in the mag which still fits under the closed bolt. Two shots if need be...after two shots..precision is likely no longer part of the equation.
I avoid going more than a couple of thou in the lands with hunting bullets, as to tight a jamb can leave the bullet in the barrel on ejection...and a mess of powder that prevents closing the bolt...big trouble in the field.