Changing a load formula
-> Reloading Ammunition

#1: Changing a load formula Author: lesterg3Location: Dixie PostPosted: Wed Dec 10, 2008 2:00 pm
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I have been looking at the Hodgdon reload table for a .270 Winchester, with a 130 gr bullet.

Here is that formula:

Bullet
130 GR. HDY SP

Powder
Supreme 780

Dia
.277"

C.O.L.
3.180"

Starting Grns
56.4

Vel
2906

PSI
55,000

Max Grns
60.0

Vel
3043

PSI
61,900

This also uses a Win Large Rifle primer.

I have also checked out a 130 grain load in the Lee Modern Reloading Manual. The formula is not as explicit in the brand of bullet, it just lists 130 grain jacketed bullets, but for a powder with similar velocity at min grains (H1000) the starting load is 61.0 grains, and max is the same at 64.0 grains. It does not mention what primer to use, and lists the Min OAL at 3.280.

That seems to be a considerable difference to me, yet a rookie, please be patient. So, I am a little frustrated at the difference.

And, here is the real question. I have no problem with the Hodgdon formula, except I want to use a 130 grain Sierra Game King BT Spitzer, and a Federal Large Rifle Primers #210. I will be using Winchester brass, which is consistent with the Hodgdon formula.

I have searched every where for the load I want to make, I can find several that are close, but none dead on. Do you really have to buy every loading manual out there? Mad And, if you do and the data is not available for what you want to do, what then? wtf

Or, do I just downsize the powder load, to say 85% of the published minimum load and build up from there? Seems like a lot of powder, bullets, etc., etc.

How do you modify existing load formulas for components such as bullet configuration, preferred primers, Min OAL, and the like.

Guidance would be appreciated.

#2: Re: Changing a load formula Author: gelandanganLocation: Sydney Australia PostPosted: Wed Dec 10, 2008 3:02 pm
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I use QuickLoad to start a new load using new projectile or powder.

Gives you an "educated"estimate of the pressure, and velocity based on the powder, projectile, OAL,temperature etc etc..

Good value for money if you like to experiment or wildcat.

#3: Re: Changing a load formula Author: gelandanganLocation: Sydney Australia PostPosted: Wed Dec 10, 2008 3:03 pm
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haha 43 posts to go.. I may make 1000 before the end of the year after all Very Happy

#4: Re: Changing a load formula Author: moose2Location: North Idaho PostPosted: Wed Dec 10, 2008 4:54 pm
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Here's what I would do. I would call Sierra @1-800-223-8799 and talk with one of there Bulletsmiths. I do it it all the time. They are great people to talk with. They will help you out. They are set up to do just that. Good luck with your reloading.

#5: Re: Changing a load formula Author: PumpkinslingerLocation: NC foothills PostPosted: Wed Dec 10, 2008 6:17 pm
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Lester, I understand your confusion, been there many times myself. That is the one thing I don't like about the Lee manual, it lacks details such as barrel length, etc. I pretty much take the velocity info there with a grain of salt.

You are doing the right thing by paying attention to the details of the various loads, such as OAL. The old saying "The devil is in the details." is sure true in regards to reloading!

When I pick a particular bullet I start off with that manufacturer's suggested loads. If you don't have that manual you can look online or email/call their customer support for info. All of the various folks I've contacted have been very helpful.

One thing I would stress is that I would never expect "similar" powders to have the same max charges. Just because they are similar in burn rate doesn't mean that the densities, etc are the same.

#6: Re: Changing a load formula Author: GrumulkinLocation: Central Ohio PostPosted: Wed Dec 10, 2008 6:27 pm
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This is what I do:

1. I use any brand of brass I want to. It's usually Remington or Winchester but sometimes Hornady, Norma or Lake City. For the 270 Win. it doesn't matter what brass you use for your starting load. You will determine the maximum load for your firearm by reading pressure signs on the brass, on the primer or in the barrel as well as by taking maximum published loads into consideration.

2. If I'm using a 130 grain bullet, I will use any data from any reloading manual to get a starting point in load workup as long as the bullets are of similar construction. That means if I'm going to be using cast bullets I use data for cast bullets. If I use copper jacketed bullets I use data for copper jacketed bullets. As long as different sources of load information are available, I use and compare at least 2 or 3 sources of load data to come up with starting loads.

3. In cartridge cases the size of 22-250, 308 Win. and on up, the primer you use usually makes very little difference in pressures but can have a significant impact on accuracy. I've used all sorts of primers in all sorts of cases so know this from experience. Remington large rifle primers seem cooler than others so in a case of 270 Win. size you might need 1 or 2 grains more powder to have a load equivalent to those worked up with other types of primers.

The publishers of the Lee manual are not in the bullet making business so don't have to push a particular brand. That's probably the reason they're not specific on primer to use etc. because it really doesn't make that much difference from a safety standpoint.

#7: Re: Changing a load formula Author: MagnumManiac PostPosted: Thu Dec 11, 2008 12:24 am
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Lester,
One word of caution here, NEVER reduce the starting loads listed in any manual, no matter what advice you may have been given.

The solution to your problem is quite simple:
Use whatever manual you're comfortable with.
Follow their data for the particular bullet WEIGHT, not brand.
If the rifle is familiar to you, you can start your loads at 5% below maximum listed charges, normally a 3 grain reduction.
WORK UP SLOWLY from the starting load. (3 rounds per charge.)
STOP when their is even a slight high pressure sign ; ejector marks, embossing of machining marks onto case heads or sticky bolt lift.

As to you wanting a certain level of performance, no loading manual will give the same results as your rifle, they use pressure barrels to test their loads, and then switch to factory rifles with those loads and get their velocity readings.
These particular loads they print are SAFE in their pressure barrels, which generally give HIGHER pressures than factory rifles do, therefore the same loads fired in factory guns will give LESS pressure and velocity with the identical loads, but NOT ALWAYS.

YOU need to 'work' your loads to find what is the best accurate/safe load for YOUR RIFLE.
BTW, velocity is not everything, as you will find out as you progress, most listed velocities for the 270 are unobtainable due to most rifles having 22" barrels. Don't try to OVERLOAD your gun to reach higher velocity or match what the manuals print. My 270 runs @ 100fps slower than nearly all manuals.
Cheers.
MagnumManiac.
Very Happy

#8: Re: Changing a load formula Author: English MikeLocation: Whitehaven, Cumbria, UK PostPosted: Thu Dec 11, 2008 9:25 am
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Some loads for the Sierra 130gr Game King listed here
Others here

If no minimum load is listed, then reduce the max load by 5% for a starting load.

Use the OAL suggested for the cartridge/bullet combination, or the SAAMI maximum OAL for the cartridge if you can't find the specific combination.
For best results, use a cartridge OAL gauge, as every rifle has minor differences.

Lyman's 48th edition reloading manual has the following information for the 130gr Game King:

3.250" OAL
Primer Win WLR
Case Winchester.
Barrel length 26"

Powder H4831
Starting load 52.0
Velocity 2726
Pressure in CUP 40,200
Max load 58.0
Velocity 2990
Pressure in CUP 50,900

Note that CUP is NOT the same as PSI.
Lyman's loads for the .270 are a little on the conservative side IMO.

The other powders listed for the Sierra bullet are as follows:

IMR4064
Varget
H380
H414
IMR4350
N160
Reloder19
XMR3100
IMR4831
Reloder22
IMR7828

Let me know which powder you're interested in & I'll post the load data. Better still; buy Lyman's 49th Edition manual, as it's one of the best out there & far more than just a list of cartridges & loads.

#9: Re: Changing a load formula Author: DawgdadLocation: On the Prairie PostPosted: Thu Dec 11, 2008 2:57 pm
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Lester---- I am going to give you something to keep you up a few more sleepless nights...Check out this link. It does not really answer your issue about a loading manuals varying wildly but it gives you a place to go once you figure out what a max load is.

OCW method

Read through this and it will give you a plan where you can use a load's maximum listed charge from a published source and back it down 5-7% then increase in 1% increments to find a load that is a winner in your gun.


For example - you have English Mikes Lyman data for the bullet you want to shoot and a powder you have in hand.

Quote::
3.250" OAL
Primer Win WLR
Case Winchester.
Barrel length 26"

Powder H4831
Max load 58.0
Velocity 2990


You would load up 3-5 of your Sierra bullets at the following charge weights using the same primer,case and OAL for all of them. ( You only really need three but it is better to have a couple of extras for a called flinch or some other failure)


Sighters - 54.0gr

First Test group - 55.4gr

Second Test Group - 55.9gr

Third Test Group- 56.5gr

Fourth Test Group- 57.1gr

Fifth Test Group- 57.6gr

Sixth test group- 58.2gr

Shoot the sighters and adjust you sights to be in the middle at your chosen distance. Once set, do not change any scope settings while you are in this process.

You shoot them at six different targets at least 100 yards away. You shoot them in sequence order, one at a time. Test group 1 to target 1, Test group 2 to target 2 etc. until you have run through the test groups 3 times. Do not shoot all of Test group 1 then all of Test group 2. This will keep the changes in conditions spread out across all the test groups. Note group six is above listed max. This is a check to see if your gun shows high pressure with this load. If it or any other test group shows high pressure do not shoot any more of that group or go to any higher powder level.

You then look for three test groups in a row that have the same point of impact. It may be two inches high and an inch to the right but it will be near the same place . For the sake of demonstration lets say that groups 4,5,6 all printed two inched high and an inch right. You Optimal Charge would be Test group #5 at 57.6 grains. To verify this, (another reason to make 5 bullets) shoot a group consisting of one bullet from each of test groups 4,5,6. This three shot group should be together. It shows where a +/- 1% change in the powder level does not affect the trajectory of the bullet. This way if the scale is a bit off one day from another you will not see a change in your load. You know you are in the middle of a sweet spot for the gun.

You can tweak the group size then by increasing the OAL by .005"-.010" until you reach magazine length or less than one bullet diameter in the case neck. Most times I do this exercise the grouping is near MOA anyway so tweaking is not real necessary.


All of this depends on how well you can shoot from a bench too. If the best you have ever done with factory ammo is 4" at 100 yards it will be hard to figure this out. Cool

#10: Re: Changing a load formula Author: fireball 3Location: northern calif PostPosted: Thu Dec 11, 2008 6:47 pm
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Very Happy While I don't load for a 270, my go to data manual is a book called loaddata usa. It has data for powder brands, bullet brands,w/ start and max loads. It even lists the most accurate load..The book lists also the primer,rifle and barrel length ..I alway use the starting load, then work up by 1/2 grain till I get max performance that the particular rifle likes. I like them cause they list for 1 particular cal/rifle.This is just my thought on the subject...Dave



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