H4895 and IMR 4166

MotoHunter

New member
So I've been doing some load work using these two powders for a new .308 I have. Found a nice load for each one and there really wasn't a difference between the two. So I loaded up another batch using the IMR 4166 because of the temp stable properties of it with winter coming on, at the charge weight that worked the best. And I've gotten better at case prep for handloading so I thought all was good. Went out and checked them out at the range and they are not acting the same as the testing loads, not even close. Shooting a 3" group now, not the 3/4" I was getting before. All components were the same as before, any advise?
 
has it been awhile since cleaning the barrel?
ive got a 308 and working up a load for 2 of my buddys 308s.
2 of them will not shoot worth a flip on a clean bore. but my 308 which is older and has thousands of rounds thru it, doesnt matter if its clean or dirty, it shoots consistently good.

Only time ive had one open up like that was with a clean bore.
 
did you change anything - like annealing the brass?

did you use the same headstamp brass as you did when you worked up the loads? something as simple as doing load workup using LC10 and then using that data in LC04 could make a difference, especailly if you were right on the edge of a node with the load you selected. or doing the load workup with winchester brass and then now switching over to FC brass. etc.

also was it the same batch of powder? if you switched canisters the new lot number you got may be just a little different than the old stuff.
 
When you were working up groups, did you see these large swings in accuracy, with small changes in powder charge?

Give us more details on what you were loading, like grains of powder, what case...

Check your action screws, base screws, ring screws.
 
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I used all the same components as before, same brass, same lot of powder. But I did pull the barrel to look at the so called pillar bedding in the stock, but I re-torqued the action screws to the same amount as it was when I took it off. I thought about it before pulling the barrel but figured I better see what happens to it when I do. I guess that answers my question. I am not happy with the factory pillar bedding and am going to replace the pillars and bed the front of the action and start over with the load development. This is a new rifle and I just started getting some loads worked up for it. Thanks for your help.
 
Might wanna check rings, bases and scope just to see that something there didnt go awry in the mean time. When I've had that much change with the same gun and components, it was scope/rings/bases. Couldn't see anything with the rings and bases either, but in that case the gun had been dropped. Switched 'em out, and back to normal. I would suspect pulling the action as the big, obvious suspect right now on this one .
 
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Now I must ask what rifle? Is something in a bind, mag box on Remington 700's can cause a action to rock. Tang safety Rugers are sometimes picky on screw tork, as are some Winchesters. I have seen a aluminum bedding block with a small bur in the lug area that drove me crazy. Good luck finding your problem.
 
It's a Mossberg MVP LR in 7.62. I got a Mossberg MVP Predator in 7.62 shooting less than 3/4" at 100 yds with the 18' barrel. Sold it and bought the LR with 20" barrel and bench rest style stock that was pillar bedded. Not real happy with their pillar bedding though. Gonna work on the stock a bit, and swap out the trigger with a Timney before continuing the load development.
 
Originally Posted By: MotoHunterSo I've been doing some load work using these two powders for a new .308 I have. Found a nice load for each one and there really wasn't a difference between the two. So I loaded up another batch using the IMR 4166 because of the temp stable properties of it with winter coming on, at the charge weight that worked the best. And I've gotten better at case prep for handloading so I thought all was good. Went out and checked them out at the range and they are not acting the same as the testing loads, not even close. Shooting a 3" group now, not the 3/4" I was getting before. All components were the same as before, any advise?

Describe your load work up and why you chose your powder charge and seating depth. My first thought is your seating depth window or powder node window is too narrow so your load work up data will help diagnose problem.
 
Well I started with a couple of forgiving powders that I could get my hands on and backed off max charge about 15% and went up in .5 grain increments until I found a couple of good groups forming then went back down a little from them and started going up in .3 grain increments till I found the best grouping and no over pressure signs, which is 39.2 gr of H4895. I do notice as I'm getting close to max loads the bolt will stick at the top of it's stroke just before opening, but no signs on the brass. The bolt sticking is why I stopped at 39.2. I'm loading up 168 gr Sierra HPBT's
It is a magazine fed rifle so I'm limited on seating depth testing and have just loaded to the max the mag can handle. COL is 2.80 but I have pushed that up to 2.88 a couple of times with the bullet jumping about .009". I really haven't done much seating depth work on it to be honest, I'm still trying to get max velocity without over pressure issues. Doing a lot of reading and asking questions.
 
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Originally Posted By: MotoHunterWell I started with a couple of forgiving powders that I could get my hands on and backed off max charge about 15% and went up in .5 grain increments until I found a couple of good groups forming then went back down a little from them and started going up in .3 grain increments till I found the best grouping and no over pressure signs, which is 39.2 gr of H4895. I do notice as I'm getting close to max loads the bolt will stick at the top of it's stroke just before opening, but no signs on the brass. The bolt sticking is why I stopped at 39.2. I'm loading up 168 gr Sierra HPBT's
It is a magazine fed rifle so I'm limited on seating depth testing and have just loaded to the max the mag can handle. COL is 2.80 but I have pushed that up to 2.88 a couple of times with the bullet jumping about .009". I really haven't done much seating depth work on it to be honest, I'm still trying to get max velocity without over pressure issues. Doing a lot of reading and asking questions.

39.2 grains is a very light load. Max pressure and velocity should be around 44-45 grains depending on the case capacity of your brass.

You mentioned you are jumping the bullet .009" at an OAL of 2.88" What is your base to ogive measurement? Just trying to get an idea of the freebore in your chamber.

I would stay at the 2.80" until you get your powder charge figured out and then move on to seating depth testing. Its important to stay methodical in your load work up and only change one thing at a time. When doing your powder testing look at your vertical POI only and ignore group size. Ideally you want two groups where the vertical POI is the same even though the powder charge is a half grain different. It helps to have a chronograph but can be done by reading the vertical. Once you find two that have the same vertical, load in the middle of the two and begin your seating depth testing in .005-.010" increments with 3 shots at each depth. For example if 43 and 43.5 grains each had the same vertical POI then you would load at 43.2 or 43.3 grains and begin your seating depth testing. Sierra bullets like to jump so don't hesitate to test jumping them as much as .100" if needed but you can usually find an accuracy node .020-.030" jump. Once you get a good group don't stop there. Keep testing the seating depth until the groups start to open back up. This will determine your seating depth window and will tell you how much throat erosion you will be able to have before having to change seating depth. Seating depth windows need to be .020" minimum before I call it good.

H4895 is the perfect burn rate for a 20" barrel. I run it with 175 Sierra's.
 
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I'm using LC (military) brass so I reduced the starting loads a little more and as I mentioned the sticky bolt issue had me bugged. I wasn't sure about over pressure issues and how strong the bolt is in this rifle. I've seen 42grains listed as max for this powder in 7.62 data
 
Originally Posted By: MotoHunterI'm using LC (military) brass so I reduced the starting loads a little more and as I mentioned the sticky bolt issue had me bugged. I wasn't sure about over pressure issues and how strong the bolt is in this rifle. I've seen 42grains listed as max for this powder in 7.62 data

If you want to fill your case with h2o and give me the case capacity I can run it through QL and give you a closer prediction.
 
When I put my,guns back together I always put the buttstock on the floor and push down on the barrel while tighting the stock. Don't know if it helps but that is the way the old man told me and my brother to always do it. Hope you get it figured out.
 
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