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Posted: 10/20/2012 4:09:29 PM EDT
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Ive posted in another topic my load for my .308 and others have commented that it is mild or soft. While this does not hurt my feelings, I am some what new to loading and going pretty much off my own findings. I load 168 SMK HPBT with 41gr of IMR4895 with Remington brass and CCI 200 large rifle primers. I send them out of a 24" heavy barrel on a Rem 700. My FPS are 2500. I just chrono'd them a few days ago. But in my Serria Book it shows this runs about 2400fps so that is what I had posted. My question is what is a decent fps to try and obtain? I know most people are looking for best group and this can be obtained by different ways of the load, ie seat depth, COL, powder weight and all the components involved with that. But what is a good avg fps to look for when loading for this cal.?
Thanks King |
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The better way to raise your pressure would be to raise the charge. You should only adjust your COAL in order to minimize dispersion in your groups, not to adjust the pressure. Nor should you attempt to use neck tension as a means of playing with pressure.
What is your direct goal? I would imagine you would want the best accuracy and precision down range. What good would a 2600 or 2700 fps load be if it ruined your performance? Unless of course, your only goal was to go faster. I agree it could go faster, and also be a good performer in terms of dispersion at the same time, but that is obvious so why do you constrain yourself to the current charge weight? |
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if you are looking for a pet load here are two that work quite well in my Rem. 700
168 SMK, 46.5 gr. H380, CCI-BR primers. Shoots sub MOA and runs 2700 fps out of my 26 inch tube. Varmint load is a 125gr Nosler BT, 51.0gr of Win 748 and CCI-BR primers. Shoots really good and fast, 3200fps out of my rifle. Warning! Use at your own risk, these loads are fine in my rifle, drop down and work up for yours. Indy |
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My goal is to get the most out of my rifle. I know they are all different but I'd like to get the fastest load with the most accurate and consistant group. The reason I used the 41grs of IMR4895 was because the Sierra book I have recommended 39-41.1 grs. The best group I got at 100 yards was with 41grs. As I'm shooting more I'm learning more. I can see that some loads group better and stabilize at further than 100 yards. I'm just now getting into shooting around 500-900 yards consistantly. But at 2500 fps this is pushing it at 900. I have yet to really change things up with powder, bullets, primer or brass as I don't want to get too confused. I do take notes and use them. But I don't know enough about loading all the different components to create the best load for what I'm looking for. So for the sake of not straying further into confusion I've "limited" myself to tweaking the load I have with the components I have right now. Plus Ive already got my numbers worked out on my scope for this particular load. But I guess that's part of the fun changing it up and seeing what's better or worse. But I'm all for using a good load someone has worked up and is satisfied with too. Saves me time and moneys.
Thanks for the input guys! King |
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Seating the bullet deeper will have a microscopic effect on chamber pressure and speed.
You'll have to add gunpowder, and you'll find out that you can probably get to 45 grains of IMR 4985 with a 168 grain MK without problem. That will yield about 2700 fps. Always try to consult more than one load manual. Look at the data from the bullet manufacturer, and look at the data from the gunpowder distributor. |
| The Sierra manual tends to be pretty conservative. It's a good manual, but it seems to really play it safe. For example, the hodgdon Load Data Center ( via the Hodgdon website ) shows 41 grains of IMR4895 as a starting load. They show max as 45.4 @ 2758 from a 24" barrel, but they also used winchester brass so their data won't be identical to yours. At any rate if you aren't showing pressure signs now you'll be safe to bump it up pretty significantly. Odds are pretty good there will be another accuracy node at a higher charge. Possibly more than one. |
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If I was looking for max velocity I would research several data sources and find the powders that deliver the highest velocity. Then I would look to see which ones do it with the least amount of pressure and fill the case the most. Then I would start pressure testing (primer reading) until I got what I was looking for (know that is vague at best but it's hard to describe) then I would start shooting groups and measuring velocity.
It may take a few different powders to find your goal but then again you may find it with what you are using now. Just remember that you will pay for that peek velocity with accelerated throat ware. |
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