Please help a neophyte: Load developemnt

[Jim Flinchbaugh]

I've been reloading for almost 30 years, always using a known source of information, ie reloading manuals. I have never been a student of load development. Can someone point me to a reference(s) where I can learn all about the inter-relations of the various components we use?
I specifically am on the quest to become able to decide from a list of items, say, bullet weight/design, powder & primer selection, and how to decide when to use what, with a given barrel length and rifling twist, etc.

My purchase of a Handi Rifle last winter in 7-08 is the culprit behind this quest.
I finally got it to shoot under 6 inches but I am noticing that any load over minimum suggested starting velocities goes right down the toilet. I suspect that the shorter 22" barrel doesn't like what I've tried thus far.
I am deliberately not listing twist, bullet weight etc, because I don't want load recommendations, I want to learn how to choose the appropriate bullet weight, powder, etc for whatever firearm I happen to be dinking with. I can't afford to buy 12 different cans of powders, 20 different bullets etc. There should be a way to determine a good starting point based on the design parameters of the firearm?
So far, I think I have determined that seating depth has the biggest impact on vertical stringing, and powder charge seems to have the biggest impact on horizontal stringing, am I all wet?
My antics so far have been with j-words, as I could not keep 6 shots on paper at 100 yards with cast.
Best group so far has been 1.1" @100yds, consistently, but again this is with minimum loads. Anything above the suggested starting point moved into the 4" plus range instantly.
Am I nuts or am I just starting down that trail?:lol:

[375RUGER]

I have one question before this gets started. If you never been a student of load development then what was your criteria for choosing a load before?
Did you just close your eyes and point at the book and say "so be it, that's my load"?
I'm not trying to be condescending or patronizing here, I'm just asking how you decided a load was good or not and what got you to that point.

I'll be back.

[Jim Flinchbaugh]

To be honest, I always started with the middle of published information in load manuals, using the bullet weight that I figured I wanted to use for a particular purpose.
For instance, When I bought a 338 Winchester, 225-250 grains seemed reasonable enough for elk. I pick a medium starting point. It shot .650" groups at 100 yards first time out. Project over. ( Don't tell me belted magnums cant shoot sub MOA :p )
My 280 Remington was the same way. Wanted to use 140 grain Balistic tips for best combination of trajectory and killing power on deer and antelope. Picked a medium+ load of 47 grains of H4831sc and it shot good. Switched from WW to CCI primers and it will shoot half inch groups to 300 yards all day long, if I am on my game. Quite honestly, I never had trouble getting accuracy or performance. my 308 Win's where the same way. Mainly luck of the draw I guess.
I've never had to chase one around before. Now I am being forced to learn something new and actually enjoying it -to a point.
I like my stuff to work, when it does- I use it and enjoy it. I dont keep messing around with other loads. It shoots good, it kills well, I enjoy it.
I lack patience for screwing around with stuff as get older- this is an exercise to deal with that I guess. :)

[Jim Flinchbaugh]

I'm not trying to be condescending or patronizing here


Not at all, you're trying to see where I am. Fine with me.
I am looking to develop some expertise with this.
I read about folks having an idea if using this or that powder burn rate with this bullet in a give barrel of a certain twist /length- I know not where that knowledge comes from except years of experience and dollars spent. If that's what it takes, I'll be out of this one and the Handi will go away as I cant afford it then.
Oh, and Graybeard outdoors is not an option, I would get banned if I spoke my mind there:takinWiz: [smilie=l:

[DCM]

OK you have a fixed twist in that barrel and a reasonable velocity that the cartridge will do so I would start with that and go here http://kwk.us/twist.html to determine the heaviest bullet that will work in your gun at the velocity you can safely achieve.

With that out of the way we get in to a lot of personal preferences.
I like a clean burning powder which means that most or all of it will be burnt before the bullet exits the muzzle so that puts me looking at the faster burning powders recomended for whatever bullet I choose. (slower powders will produce accurate loads also but usually not as clean).

So there is bullet choice too.
This mostly depends on the intended use, vermin deer etc.
Vermin any accurate bullet will work, but lighter ones are usually used for low recoil and less over-penetration.
For larger game I want an exit hole, it makes for much better tracking when they don't go down right there, which WILL happen at times.
Bullet design and weight are key factors for an exit strategy. Usually heavy for caliber but not always with proper alloy and design.

Primers: is the powder of choice a very slow burning magnum type, then a magnum primer is in order to consistently light it.
"Non magnum" powder standard primer.

Cases: Most folks use what they can get. But one would be wise to sort them by brand at least as some brands are far different than others.

Seating length will often be determined by what will actually work out of your magazine or by measuring the throat, whichever really works for YOU.
I DO NOT like stuff touching the lands, IMO you are playing with a bomb YMMV.
Varying your seating depth effectively increases or decreases your case volume so you will be increasing or decreasing pressure to some degree. If you are just starting out I would HIGHLY recommend using the recommended O.A.L. as it will give you the best predictability.

Charge weight: I load small lots in 0.3g-0.5g increments, start low and work up looking for accurate groups, pressure signs, leading and anything strange.
Often as you climb the ladder towards max you will find more than one sweet spot for accuracy, sometimes not.

As for trying to find an accuracy load off the bat I look in the books and see if they list one, I also ask around BUT check any suggestions against the books to see if they are considered safe.

If you want more info I can give you a couple of good links on OBT and OCW loading, but both of those assume you are very familiar with reloading to start with and one is extremely technical to some folks.

If you tell us specifics we can help steer you down the lower cost road to finding a good load.
I load for a lot of calibers, have a LARGE stack of manuals, Quikloads and have spent more on equipment than I want to admit so I don't mind helping others save some$.
That was why I started reloading in the first place.

[375RUGER]

First thing you do when a gun won't shoot anything is define what the problem is.

Is it the gun or is it the load?

If it's the gun then you will chase your tail for years if you are trying to find the right load.

Have you shot any factory ammo?
I'm sure the handi was designed to shoot most common factory loads avavilable.
I'm guessing that it will shoot anything from 120 to 140 really well. If you experience the same thing with factory ammo that you are experiencing with handloads-then it may not be the ammo or the manufacturer-it may be the rifle.


Do define the problem first and foremost.

You say vertical stringing. Are you positioning the rifle on the rest the same way everytime? Is there foreend contact with the barrel? ( know there is on your rifle)
Is the contact irregular in any place?

Is stringing your only problem?

Check the crown. If it is damaged or irregular in anyway that will cause bad groups.

There is no reason a 22" barrel can't be accurate. But barrel harmonics may not be right for any load you try. You might have to cut of .250" and recrown, might make a world of difference, it might take .500". Might not be the problem at all.
I've heard of people attaching a weight to their barrel to change the harmonics. I've never done it so I can't give any recommendations.

Here are the questions that go through my mind when I want to develop a load. I always develop for accuracy whether it be hunting load or target load.

Bullet selection-what do I want to use the rifle for, varmint, big game, target, etc.
You can use any J-word you want here.

Twist and bullet length- fast twist stabilizes long for caliber bullets and slower twist for shorter and more caliber appropriate bullets.

Check barrel manufacturers websites, i.e. Shilen, they give recommendations of twist based on the bullet style or weight for each caliber. there are formulas and charts out on the web.

Bullet seating depth-
You are not limited to magazine length so you can push that bullet up into the lands so that you get a mark on the bullet about 1/2-1 land width. This may be to much, you might find that .010 or .020 or .030 etc may be best for your rifle. That is load development. Effectively what you are doing is changing the amount the bullet has to jump and your total case capacity. Your rifle will tell you what it likes.

Bullet runout- Especially when I want accuracy I check that. If you have .015" (or more) variation in the way a bullet starts to engage the lands then you have a .015" variation in the way a bullet exits the muzzle at the other end. Bullet runout can be solved by fixing your dies, usually the sizer.

Case prep- I only neck size when I can. I have a couple rifles that get full length but I don't need the loads to be rifle specific for those rifles at this time.

Powder-I like to find out what everyone else is using for a particular bullet. If there is a general agreement that this powder and this bullet/weight combination is good then I may very well start with that powder. Usually you will find 2 or 3 powders that are known to be good for a particular cartridge/bullet combination.

http://www.handloads.org/loaddata/default.asp?Caliber=7%20mm-08%20Remington&Weight=All&type=rifle&Order=Powder&Source=

http://www.centerfirecentral.com/Searchreload.asp

Load manuals are a good place to start-if a powder is not listed for a particular load it may very well not be very good. Or it may not have been tested for that particular cartridge.

I like to find a powder that fills the case as much as reasonable.

Powder charge- I start somewhere. Usually on the light side of a range of recommened loads. I don't waste my time with the lowest possible charge. I go first in .5g increments till I think I will reach the max. When I find a load that shows promise I go back then work up and down in .1, .2, .3 g increments.

Primers- I choose a magnum if cartridge capacity is large and I think the powder will benefit from the extra kick. I choose match when I want to ensure consistency. What primer was used in the load manual?

I'm outa breath, maybe I'll think of more later.

Sometimes you have to burn a lot of powder to get a load. Sometimes you have to try a bunch of bullets. It all depends on your requirements for your usage case.
Sometimes you just get lucky-like I did with the first rifle loads I ever made. I made 5 and went to the range and shot a .444" group with my 7mm Mag. And the cool thing is that load and rifle will still do that. I don't think I've been quite that lucky since.

[375RUGER]

I was just checking the H&R website and I don't see any 7mm offerings for the handi rifle. Do they not offer the 7-08 anymore? or is this a rebarrel?

[Jim Flinchbaugh]

7mm-08 is still on the website, at least it was earlier today.

As I approached the recommended seating depth of 2.850, the vertical stringing went away.
I checked the Hodgen site today and they say 2.75 for the 120 grains I was shooting.
So far I've tried 120 & 140 ballistic tips, with both Benchmark and Reloader 15. The 140's with Rel 15 gave the best group at minimum starting loads, groups went down the tubes as soon as I went up a grain.

The cast boolits I tried where seated to the base of the case neck, as it is a bore rider. That could have been my issue there.
I'll try and find a better way of what I'm after before I explain more.
Thanks so far

[Blacksmith]

Did you slug your barrel to check diameter and see if there are any tight or loose spots? Is this a brand new barrel with very few shots through it?

[375RUGER]

7mm-08 is still on the website, at least it was earlier today.



I could have been looking right at and not seen it. Especially yesterday, the wind was out of the wrong direction and diesel generator fumes were coming into the building. I eventually had to leave from blood coming out my nose, sore throat, and head swimming. Anyway, got to go home and make 74# batch of alloy [smilie=w:

Seating depth-you can find out how long the throat is using a fired case, deprimed. Either drill out the primer pocket or find a small stiff piece of wire that will fit through the flash hole. Place bulllet in the case neck and carefully insert into chamber. Push the wire up to the base of the bullet until the bullet contacts the lands. Mark the wire. Remove everything and reassemble using the mark and you can measure the OAL for that bullet. The only thing this accomplishes is you now know how far that bullet is jumping to the lands.
I usually start mine .020" back if bullet length allows.

Lots of things load and gun related can cause vertical stringing and inaccuracy.

Scrub the dickens out of the barrel with JB bore cleaning compound and see what happens. Make sure it's not just a fouled barrel.

How much off center is the firing pin strike on the primer? Off center firing pin strike will cause inconsistent ignition as well as cause the cartridge to get cocked out of alignment.

[singleshot]

Jim,

First, you shouldn't necksize brass for the Handi, or any other break-open gun. The action is too springy for that to produce good results. Second, that rifle design is extremely sensative to head space. It must be exactly right. Too little headspace will cause verticle stringing. You want .001" of headspace. As far as factory ammo goes, it is of sketchy quality when it comes to headspace. "Top-shelf" factory ammo can have headspace variations of .004" or greater. I've seen examples that were .008" different from smallest to greatest in a single box of ammo! That's fine for a typical bolt-action, not for a break-open action. (But that's also one of the reasons you can reload more accurate ammo than you can buy.) It's not that hard to control headspace of the round, but sometimes there is insufficient space between the barrel and frame, .0005" seems to be optimal, the other .0005" for the round itself.

Another issue is verticle stringing from barrel heating. Last time I checked, H&R barrels were not stress relieved, as they heat up they contort more than other barrels. I had a 25-06 H&R that would shoot the eyes out of a gnat at 300 yards on the first shot. Each subsequent shot would walk off the paper and by shot #5, where the shot would end up was anybody's guess.

Bottom line: Two very important items to check and verify or rule out for that rifle are ammo headspace and barrel heating and are the most common reasons for your type of rifle to exibit verticle stringing. I would not move on to other factors until those were ruled out and or verified.

[41 mag fan]

This is and can become a very interresting thread. Very informative how individuals come up with loads.

[felix]

The strength of the firing pin spring, plus the length of the firing pin itself, are both additive to the headspace dimension. ... felix