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DPSTex
HB Full Member
| Joined: | 15 July 2008 |
| Location: | Leander, Texas USA |
| Posts: | 13 |
| Photo: | | | Are you a handloader?: | Yes | | Favorite type of cartridge to load?: | rifle |
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Posted: 9 September 2008 05:21 AM |
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Let me apologize now for the length of this, but I have some questions for which there may not be any easy answers, and there is likely someone out there who can shed some theoretical light on my subject!! I have a 243 Win, Model 70, that is (so far ) the only rifle I've ever loaded for. Used to be just for money saving hunting rounds, but now that I've found a good range nearby, I've been experimenting with increasing the accuracy of my ammo. I've been using as many of the tricks that I've learned that I can afford and even experimenting along some of my own ideas. I've only ever loaded with IMR 4350, and sierra 100gr btsp's and Nosler 80 gr BT's. I've been using Winchester brass. I've played with powder charges, seating depths, and different primers.Cases and bullets all get weighed and sorted by weight, trimmed for length, Neck sized only (all that a Lee hand Target loader will do), charges are all weighed. It's pretty easy to get the rifle to shoot .75 groups at 100 yds with either of these bullets and this powder and I've worked most of the combinations I can within the components listed. I realize that 3/4" may be the limit of the rifle but I have plans to try some Lapua brass and a Berger 90gr bthp when I can afford to procure some. My next experiment is changing to hodgdon H4350 and rerunning some of my tests to see if this powder will be more consistent. What I wanted from my next powder was something that would allow me to fill the case more without overpressuring or getting such a slow burner that the muzzle blast gets out of hand. Part of my problem is that I am going to increase my overall cartridge length to put the bullets just on the lands. This is only .004" farther out than I've been seating my bullets. I guess my point with this part of the question is that much of the load data that I've been using as my base, suggests much shorter cartridge lengths and my understanding is that a pretty full case contributes to accuracy as does putting the bullets just in the lands. I chose the h4350 because I have data from speer that shows about 2 more grains of this powder for similar velocity on several different bullets in the 243. (be assured that I will not swap the load data grain for grain, I'm starting low and working up) This seems to show a trend that would allow me to work up a load with equivalent performance to the IMR, but possibly more accuracy due to the fuller case. I hesitate to go slower yet with my powder choice because of the potential for increased muzzle blast from my 22" barrel. Also most of the reading I've done suggests that 4350 is like THE powder class for the 243. Most don't say much about the slower "4831" class of powders in a 243 with heavy bullets. Am I thinking about this in the right way? Is there a chart somewhere that indicates average case capacities of different brass manufacturers, a case smaller inside would allow me to compensate for my long chamber. What are the advantages, disadvantages to compressed loads, (although I don't think I would be able to use them unless switching case brands would tighten up the case capacity)
The action is already glass bedded and the barrel floating, my magazine will handle cartridges .060" longer than anything I've thought about loading.....
Thanks in advance!!
DPS
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What did those big sheets of paper ever do to us?!?!?!?!?
DPS
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wheezengeezer
addicted handloader
| Joined: | 16 July 2007 |
| Location: | Jeddediah Jones Swamp, Kansas USA |
| Posts: | 708 |
| Photo: | | | Are you a handloader?: | Yes | | Favorite type of cartridge to load?: | pistol |
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Posted: 9 September 2008 05:28 PM |
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| the difference in case capacity will be a very small percentage. i dont understand what you mean by this, " a case smaller inside would allow me to compensate for my long chamber." the only advantage to a compressed load is if you need that much powder.ball powders compress little,extruded compress some.too much will break the powder kernels,bulge cases or bullets will back out.avoid excessive powder compression,go to a bit faster powder instead.
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I was raised in the 50's on gunpowder and jackrabbits.salt and pepper wooda made'em taste better
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DPSTex
HB Full Member
| Joined: | 15 July 2008 |
| Location: | Leander, Texas USA |
| Posts: | 13 |
| Photo: | | | Are you a handloader?: | Yes | | Favorite type of cartridge to load?: | rifle |
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Posted: 9 September 2008 06:07 PM |
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WOULD a case smaller inside allow me to compensate for my long chamber? To get my bullets to seat just in the lands of the rifle, my seating depth is shallow compared to SAAMI overall length specs which leaves the inside capacity large. with the winchester brass, the 100gr btsp bullet and 43 grains of imr 4350 and my seating depth, there is still plenty of room in the case for more powder but my case heads stretch with this load, (new primer is loose fit) I'm wondering if I'm thinking correctly that by going to a slower powder to better fill the case will make the burn more consistent. or if a different brand of case will possibly be smaller enough to make a difference? In order to compress a load in this combination, I'd have to push the bullet in to the ogive. Another question is... is the brass I'm using possibly weaker than other brands showing signs of overpressure before another brand would???
Onward thru the gunsmoke !!!!!
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What did those big sheets of paper ever do to us?!?!?!?!?
DPS
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wheezengeezer
addicted handloader
| Joined: | 16 July 2007 |
| Location: | Jeddediah Jones Swamp, Kansas USA |
| Posts: | 708 |
| Photo: | | | Are you a handloader?: | Yes | | Favorite type of cartridge to load?: | pistol |
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Posted: 10 September 2008 02:37 AM |
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your questions indicate that you havent studied loading manuals much.i am talkin about the section before the data.there is no substitute for doing so.you will get a lot better grasp on the subject.
handloaders want more case capacity,it allows a larger powder charge.if you have problems with pressure with a case less than full,a slower powder may be better.bullet seating depth/coal/distance from the rifling MAY be the biggest variable in accuracy that you can play with.just remember,every combination of load and rifle is different.only YOU can determine which combination works best.you just need to know how to manipulate the variables.it does get a bit addictive,be carefull.or you will have more toys than room.
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I was raised in the 50's on gunpowder and jackrabbits.salt and pepper wooda made'em taste better
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miestro_jerry
HB Life Member
| Joined: | 28 June 2008 |
| Location: | Somerton (AKA BFE), Ohio USA |
| Posts: | 776 |
| Photo: | [Download] | | Are you a handloader?: | Yes | | Favorite type of cartridge to load?: | I load everything! |
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Posted: 11 September 2008 12:37 AM |
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When I have a compressed load, I start looking at other powders.
There is a huge amount of data out there for reloaders and some resources have what is consided to be the pressure for that load, with that weapon, powder and bullets. I never start near the top of the data.
If I get a flatten primer, that indicates that I have too much pressure and to back off some. This load that flatten my primer may work great for you.
So enjoy reloading, do things safely and enjoy shooting.
Jerry
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A Closed Mouth Gathers No Foot
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