I have been working up a new load in my .243 win with spr 100gr btsp with 40gr of H414 and mag primers. I can't get them to group worth anything. Could this probem be caused by the gun just not liking this bullet or is it a powder issue? I don't want to go out and buy two or three different bullets and powders to try and figure it out on my own so I am asking you guys for some advice.

I had trouble as well with a 243. I tried several diferent bullets and powders to find something that would group decent. If you moved up in bullet weght, the rifling may not be fast enough to stabilize the extra length. I know my worst groups were with 100 gr. and above. I settled on 95 gr. hornady sst.
Don

Check out this link:

www.huntingnut.com/ind...cle&sid=17

If you have more question after you read this article, check out Dan's sit:

www.clik.to/optimalchargeweight

or his forum

(Do a Google search for the address)

excellant reading there.. I was going to ask if the OCW was worked up for the rifle/round but ya seem to have beat me to it there. I use 38 gr of H414 with nosler 100grain partitions out of my savage .243 and have good results with them, of course diff firearms require diff charges and some just plain dont like certain bullets..

It could be the rifle or the powder charge or a host of attendant issues, tech spec man. In general, my experience is that good rifles are not overly particular on bullet weight or powder charges, presuming that they are selected within the normal standard regarding twist and volumetric fill.

Regarding load development: While OCW has some good insights into accuracy consistency, another factor is volumetric fill of the case. I prefer my handloads to fill at least 90% of the case volume*. Burn rates and bullet weight dictate which powder(s) will accomplish this. If we apply this idea to the use of H414, we find max load data achieves around 80% fill with 100gr bullets. IOW, moving to slower burning powders will increase the charge weight and the fill %.

Reloder 19 and H4350 are in the same appx burn rate as H414, but, are bulkier powders and increase volumetric fill. Along with Reloder 22 and H4831sc, they offer better fill. The last several editions of the Nosler manual have shown that volumetric fill, accuracy and velocity often coincide. The most accurate powders in most bottleneck cartridges offer higher volumetric fill and the attendant velocity.

I use H414 in 243 Win with 55gr and 70gr bullets. Both these loadings allow 90%+ fill rate and both are subMOA. If you are developing 243 loads with 100gr bullets, I would suggest trying slower burn rate powders.

*Codifying the relationship between powder charge, optimal pressure and accuracy was one of the benefits of Homer Powley's long standing research. Newberry's ideas and conclusions are worth considering, but, some added information from Powley can round out the overall view of how to achieve accurate loads at good working pressures with good volumetric fill.

Work up 85 grain TSX's with RL15 and rule the world...........................

TecSpec,
The 6mm is very choosy about bullet weight in a slow twist gun. There are volumes written on the subject. You might recall the 244 Sako rifles that had a rifling twist to slow. I have owned one of these rifles, it only shot light bullets. I have also owned several 243 guns. Suggest you stick to the H-414 but drop back to a lighter bullet. By the way, mag primers are not necessary in the 243.

Handloader,
H-414, according to the folks at Hogdon, was developed specificly for the 22-250 and with cartridge cases of similar capacity it is a real performer. Combining the 260 and max loads, H-414 will shoot .10 to .15 groups. So H-414 is not or should not be a problem in the 243.
Ed

I use Speer 100gn btsp in my .243 for all my deer shooting. 42gns H4350 and consistantly get under 1moa @ 2920fps under ideal conditions. I take when you say mag primers you mean magnum, why are you using magnum primers? These could be causing higher pressure loads than are safe, have you cronied any loads, you may be shoving them out faster than intended and not stabilizing. Standard lr primers are sufficient, I use Rem 9 1/2 lr. I'm presuming you've had good grouping with other loads/heads, what weight/ make were the heads?

Techspec: I tend to think about the primers also.
I have found significant difference in pressure signs and group size with the 2 lr primer types. I stick with the standard lr primers. Seems to work best for me. I have found H4350 to be consistently more accurate than H414. Both have worked for me..........but my standard is less than 1.5" at 100yds for hunting, not less than 1".

Tech spec man, have you used the same bullet with another powder?
Rifles have preferences, like people do. If the bullet and powder are new to this rifle, either one could be what the rifle doesn't like.
A few things I can tell you from loading 243's since about 1966.
1. You do NOT need a magnum primer with any powder in the 243. Standard primers work fine. I know the Speer manual always suggests magnum primers with ball powder- I don't know why, as no one else does, including the powder manufacturers (and they oughta know).
2. Assuming you have a factory 243 barrel, you do NOT need to worry about twist rate. The twist rate will be 1-9 or 1-9 1/2 from any factory making barrels in 243, and that twist rate will stabilize any of the 100 grainers on the market.
3. H414 is one of my favorite powders for 243 with medium weight bullets, like 80 or 87 grain. For 100's, you might try a slightly slower powder, like 4831(anyone's), 4831, R19 or R22.
4. Clean the barrel. High velocity rifles foul bores quicker- and show declines in accuracy faster, too.
Last bit of advice is to only change one component at a time, when you're trying to figure out what works. My first move, after cleaning the barrel, would be to try a different powder with the same bullet you're using now.

SwampFox wrote:

Handloader, H-414, according to the folks at Hogdon, was developed specificly for the 22-250 and with cartridge cases of similar capacity it is a real performer. Combining the 260 and max loads, H-414 will shoot .10 to .15 groups. So H-414 is not or should not be a problem in the 243. Ed

Hi Ed

H414 gives me superb performance in 243 and 6mm when used with bullets in the 75gr weight or less. Its one of my preferred powders for 220 Swift as well. For the heavier bullets I prefer slower burn rate powders in 243 Win. And, that was my point regarding volumetric filling of the case.

I would agree that H414 is a good choice in 22-250. Bruce Hodgdon's personal choice for 22-250 was a take down military powder, H380, the name deriving from using 38grs with both 50 and 55gr bullets. Its another superb ball powder that has extended uses in many different cartridges.

Any standard rifle primer will ignite powder well in the 243 Win. (I normally use WLRMs in all large rifle applications as it has the highest brisillance of any primer which can be a factor in subzero conditions.) Changing primers from brand to brand or from standard to magnum can have as much as 7,000 psi difference. Too, changing brass brands can effect pressure as some brass by brand is heavier than others. Given the finer points of accuracy, changing lot numbers of the same brass, primers and powder can also have an effect, usually not of critical importance for hunting rounds, but, it could be detectable on a good bench rifle. All of this is part of recommended reductions in loads when working with new lots and especially new brands of components. SAAMI standards recognize these minor differences in establishing normal max pressures. There is enough allowance to handle it.

I've actually gone to another slower powder, Reloder 25, in the 243 Win when using 100gr Partitions. My powder charge fills the case to the base of the neck, gives outstanding velocity and accuracy.

I have reloaded the 243 for many years and always use 100gr. Nosler Partitions. My favorite load is 39.5grs. of IMR4350 using this bullet. It is not a barnburner but it is accurate and puts the deer down with authority.

The 85 X is the killinest bullet to ever to run down a 6mm tube.............

While reloading for my 30-06,300WSM and my son's 243 I know that COL is important, so find a good spot where it isn't on the lands but loads well and fits the magazine. Different ways to accomplish this.
I've used different powders, but mostly what the manuals suggest, and I start low and ease up. What I'm looking for is an hourglass grouping of various powder loads. Maybe the lower loads have too much spread, then they tighten up as the powder load increases, then open up again as the load gets too heavy. My 30-06 likes 56.4 grains of 4350 and I can cover 5 shots with a quarter;56 or 57 grains opens up the groups. So,I work to get the most narrow cone possible within the powder weights. Barrel harmonics is what you work with using the different burn rates and powders. Just find the sweet spot and then you can fine tune with .1 or .2 increments.

my best .243 100 g load is 42g imr4831 100g Hornady and standard large rifle primers. Hope this helps you. I know "stick" powders are harder to get through the necks of smaller cartridges but sometimes that is just what it takes I wouldnt have settled on this one if it didn't work so good. As I prefer "ball" powders too. a cheap fix for your h414 load might be to try standard large rifle primers. Try it, it might be too easy.