I'm loading .260 with H4350 and having some strange results.

[8mmDale]

I shoot a Remington 700 .260 with a Criterion 28 inch pre-fit bull barrel, 1:8 twist.

I am using 140 grain A-Max and 142 grain Sierra Match Kings to develop the correct load.
Prvi .243 brass, Tula primers

I've noticed alot of loads that guys are using are 42+ grains of H4350. At 42 grains Im getting alot of burn marks on the head stamp of the case. Flattened primers as well. I dropped the load down to 41.5 and same thing, still getting alot of burn mark on the head stamp. No ejector marks on the case at all.

Not sure what is causing this, fairly new to rifle reloading. When I backed into the velocity with Ballistics AE, I was getting 2825 fps with 42gr/140gr amax.

Next step will be 40.9 as I didn't think the groups were all that great with the 41.2 I tried today. What am I doing wrong?

Dale

 

[cacoltguy]

It doesn't seem like your load is excessive to me. I shoot 142 gr. Sierra Matchkings with 42.7 grains of H4350 using Lapua brass and it gets me around 2850 fps. out of my 1:8 twist 26 inch barrel. I've found that primers arent always a good indicator of pressure signs depending on the type and how tight they fit in the primer pocket. I use Federal 210M primers which seem softer and can sometimes give the impression of being flattened in non-high pressure loads. Just out of curiosity, by burn marks on the head stamp do you mean signs of gas seeping through the primer pocket?

 

[8mmDale]

It doesn't seem like your load is excessive to me. I shoot 142 gr. Sierra Matchkings with 42.7 grains of H4350 using Lapua brass and it gets me around 2850 fps. out of my 1:8 twist 26 inch barrel. I've found that primers arent always a good indicator of pressure signs depending on the type and how tight they fit in the primer pocket. I use Federal 210M primers which seem softer and can sometimes give the impression of being flattened in non-high pressure loads. Just out of curiosity, by burn marks on the head stamp do you mean signs of gas seeping through the primer pocket?

Yeah, thats what it seems like. Ill see if I can get a picture of one real quick.



Best group, thats a 1" square at 100 yards. I think more of it was the load than me, I felt my shooting was pretty squared away today.

 

[cacoltguy]

Do the primers seat with a bit of force or do they seat very easily? I've never used Prvi brass or Tula primers before but perhaps the primer pockets on Prvi are a bit on the large side (Not sure if Tula primers are considered soft or smaller in diameter compared to others). I've definitely found that different primer/brass combos can vary in how tight they seat. You would think they are all the same dimension but they aren't. Primer cup diameters can vary by a few thousands of an inch depending on manufacturer. If this is the case the primers might not be fitting tight in the primer pocket thus allowing some gas seepage and also allowing the primer to back out easier upon ignition and smash up against the bolt face which would flatten them.

 

[Papagallos]

Welcome to the reloading club. Now, there can be different variables at play. You are going to have to test one at a time, sort of.

But first, tell us a little about the rifle. Is this a new rifle/new barrel? If it's not a new rifle, what powder were you using before?

Possible Variables:

1. H4350 is running "hotter" than normal. I mean this in the sense that your current lot # may take less powder to produce the same pressure levels as someone's different H4350 lot #. So just because someone was using 42g of H4350 doesn't mean that your 42g of H4350 will work without issues. Maybe 41g or less will equal the 42g of someone else's lot #. I hope I made sense. I am fairly new to reloading as well, but I, too, had issues with H4350. It's the reason I switched to H4831SC.

2. Tight chamber/Carbon Ring fouling.

3. Some pimers burn hotter than others.

4. Seating depth. Too long or short.

5. Brass. Is it correctly sized? Headspace?

6. Environment. How's the weather in your area? Too hot?

I may be missing a few other things.

I wish I could provide you with further details, but I don't have a lot of knowledge in this area. I am sure someone with the expertise will chime in.

 

[8mmDale]

Welcome to the reloading club. Now, there can be different variables at play. You are going to have to test one at a time, sort of.

But first, tell us a little about the rifle. Is this a new rifle/new barrel? If it's not a new rifle, what powder were you using before?

Possible Variables:

1. H4350 is running "hotter" than normal. I mean this in the sense that your current lot # may take less powder to produce the same pressure levels as someone's different H4350 lot #. So just because someone was using 42g of H4350 doesn't mean that your 42g of H4350 will work without issues. Maybe 41g or less will equal the 42g of someone else's lot #. I hope I made sense. I am fairly new to reloading as well, but I, too, have had issues with H4350. It's the reason I switched to H4831SC.

2. Tight chamber/Carbon Ring fouling.

3. Some pimers burn hotter than others.

4. Seating depth. Too long or short.

5. Brass. Is it correctly sized? Headspace?

6. Environment. How's the weather in your area? Too hot?

I may be missing a few other things.

I wish I could provide you with further details, but I don't have a lot of knowledge in this area. I am sure someone with the expertise will chime in.

Its a new barrel on a fairly new rifle and bolt. I've put about 300 rounds through it so far (I have the exact count but not in front of me). The prvi brass is obviously not lapua quality, but the primers dont feel like they are excessively hard to press in, nor do they fit loose. Some of them do sit deeper in the pocket than others tho. The head space is correct and I've fired this brass 3-4 times already so its been fire formed to this chamber (it did alot of the burning on the first reload). The brass was brand new never fired when I got it, so I dont think being worn before I got it was an issue. I got this rifle at the beginning of the summer, seems like its been in the 80's every time I've gone out with it save maybe one time, but I keep the ammo in these hard boxes and out of the sun light.

Seems like my loads shouldn't be that hot! And I was expecting to do at least a dime sized group at 100, not these inch groups.

 

[Nate O.]

Don't be afraid to try some H4831SC too. I got a smidge more speed and less pressure.

 

[cacoltguy]

So did you see these pressure signs on the first through third loadings or is this a new load? I'm sure you have trimmed the cases but since you didn't say I would ask that as well. If they are excessively long that could cause pressure spikes are well.

 

[8mmDale]

So did you see these pressure signs on the previous loadings or is this a new load? I'm sure you have trimmed the cases but since you didn't say I would ask that as well. If they are excessively long that could cause pressure spikes are well.

I've had to trim this brass with every firing which I think is a sign of thin/low quality brass. When I first ran it through the sizing die and turned it into 260 I had to trim it.

I might have to try the 4831 if I can't get any more 4350, I'm down to less than 3 pounds and I shoot quite abit.

 

[Nate O.]

I was getting pretty flat primers with the 4350 as well...now i use the 4831sc in the 260 with 140's and the 4350 in the .243 with 95's

 

[cacoltguy]

I've had to trim this brass with every firing which I think is a sign of thin/low quality brass. When I first ran it through the sizing die and turned it into 260 I had to trim it.

I might have to try the 4831 if I can't get any more 4350, I'm down to less than 3 pounds and I shoot quite abit.

Well I trim mine every time as well to be consistent in my process so that's not necessarily a bad thing. Who knows. What caliber were the cases originally? The velocities and loads you are posting dont seem out of the ordinary by any means and H4350 is the "go to" powder for .260. Barring any issues with your reloading process and brass/primer components maybe try another powder and see what happens.

 

[FALex]

what are the thicknesses on your case necks?

I'm going with tight necks. Easiest way to check: try to run a bullet through the mouth of a fired case. If it won't go in, you've got to shave your necks.

 

[8mmDale]

For some reason the post with the pictures of the problem got deleted ?

 

[FCS]

I shoot a Remington 700 .260 with a Criterion 28 inch pre-fit bull barrel, 1:8 twist.

I am using 140 grain A-Max and 142 grain Sierra Match Kings to develop the correct load.
Prvi .243 brass, Tula primers

I've noticed alot of loads that guys are using are 42+ grains of H4350. At 42 grains Im getting alot of burn marks on the head stamp of the case. Flattened primers as well. I dropped the load down to 41.5 and same thing, still getting alot of burn mark on the head stamp. No ejector marks on the case at all.

Not sure what is causing this, fairly new to rifle reloading. When I backed into the velocity with Ballistics AE, I was getting 2825 fps with 42gr/140gr amax.

Next step will be 40.9 as I didn't think the groups were all that great with the 41.2 I tried today. What am I doing wrong?

Dale

You made 260 from 243, unless you turned the necks you have a donut. There is about 0.080" of neck that used to be shoulder. If you load a round I bet you'll find that the section of neck is thicker (larger in diameter just above shoulder/neck junction). I'm also going to be that if you mic the neck where it is larger diameter, it is same or ever so slightly smaller then diameter of neck in your chamber.

Given you have pressure signs at 41.5gr, I suspect it is clearance / donut issue from forming 260 out of 243 brass. Until you remedy the donut / clearance issue you will have pressure signs and poor accuracy regardless of powder used or powder charge.

Won't say it is impossible, will I say I find it improbable that you are getting 2825 w/42 gr of H4350.

Generally speaking, I've found the Tula primers to flatten sooner then 210M or BR2.

What is OAL to touch lands with either bullet? How much jump are you running?

Have you tried any factory ammo w/142 SMK or 140 A-max?

 

[Ring]

ive used privi 243 brass to make 260.. out of 200 pieces, i never saw 1 get a donut... they do seem to have soft pockets... i think i blew out 30 of that 200 doing load testing, and those all have bad gas leaks permanently now...
and every so on, it will blow another.. i have separated that brass and just use it to load subsonics now..

i also have 300 RP and 400 FC/LC brass... i dont see that issue with those...

the blowout happened at 42.5gr h4350 in my Shillen savage, i backed it down to 42.3, it got better

my CBI 700, i have run to 43gr 4350 and it was ok.. but backed it down to 42.5 i belive

 

[cacoltguy]

Since it seems likely that the issue possibly revolves around the brass (either the make of it or the resulting issues from reforming it) I would suggest trying some dedicated .260 brass from one of the major manufacturers and see what that gets you.

 

[wrongside]

I don't know about Tula primers but I have checked the four major makers Rem., Win., Fed. and CCI and they all were different diameters. The difference on my calipers range from .2085 to .2105. CCI seem to be the largest so you might want to check the diameter of the Tula and go to a larger primer. Yours might not be tight enough.

 

[damoncali]

Is it possible that your chamber is a little oversized at the base?

 

[8mmDale]

Is it possible that your chamber is a little oversized at the base?

I suppose anything is possible, but I havent noticed anything weird while resizing that would indicate that. The next step for me will probably be to do as others have suggested and buy some real 260 brass. I was thinking about getting some Norma brass and trying it out.

Is it possible that odd ball brass could cause accuracy problems? What are going to be the negatives for using brass that isn't as good as say lapua or norma?? Maybe with good brass my charge can go up to 42+ and regain some accuracy and even more velocity.

 

[damoncali]

The reason I ask is that a few years back I had an old mauser that did this with factory ammo - I think it was due to a sloppy chamber. Might want to have that looked at. Regular domestic brass shouldn't do that with moderate loads. I'd check the diameter and headspace.

 

[Captain Kirk]

How much H4350 do you have? It must all be bad, I'll take it off of your hands and dispose of it in a series of small controlled explosions.

 

[8mmDale]

How much H4350 do you have? It must all be bad, I'll take it off of your hands and dispose of it in a series of small controlled explosions.

A the rate I'm testing it to make sure it's not bad, there won't be any left to give you.

 

[Supersubes]

My first .260 was GA built with a 24" rock 5R. I went as high at 42.5 gr of H4350 with the 142 and Remington brass. That was bleedin edge, and I popped some primers early on. Settled back down to 40.7 eventually and never looked back. Shot 4000 plus rounds of that ammo and the rifle freakin hammered! Absolutely incredible. Velocity was 2780. At 4300 rounds, i sold it, but it hadn't lost ANY accuracy. Never shoulda sold it. As a side note, the bore corkscrewed down the barrel, and exited off center at the muzzle. Never told george about it because it shot so well.

My current .260 is a broughton 5C 27" with a fairly large chamber and it takes 44 grs H4350 with with a 130 JLK to make 2880 fps.

I wouldn't worry about peak velocities just yet. There is a reason you are supposed to work up. Load for accuracy, then sort out velocities/ spreads.

Can you post some pics of the walls of the brass? As in a profile shot?

 

[Supersubes]

Just read you post about the brass. Good brass is worth every penny. Varying internal volume can be quite large on shitty brass. Imagine a car engine with varying size cylinders...

I currently shoot win 7-08 necked down. Works great. I'd shoot lapua in a heartbeat but my neck is too tight for that, and neck turning is a joke.

 

[JGorski]

Don't be afraid to try some H4831SC too. I got a smidge more speed and less pressure.

But not loading the same amount as you would with H4350.

 

[Nate O.]

But not loading the same amount as you would with H4350.

Nope, you'll need more of it.

 

[damoncali]

I'd shoot lapua in a heartbeat but my neck is too tight for that, and neck turning is a joke.

I'm curious as to why you think that. The way I see it there are a lot of good reasons to turn necks.

 

[JGorski]

"Competing against cartridges burning more than twice as much powder and rifles weighing up to 100 pounds, Jason's little 6BR proved to be a giant killer--a David slaying the Goliaths. Jason won the Heavy Gun title, using the standard 6BR case and Clinch River 106gr bullets. And get this, he used unturned Lapua brass, with almost no case prep."
So much for using "turned' brass, huh.

 

[damoncali]

To each his own. I'll keep the vastly improved brass life of my tight neck chambers and turned brass. Try it. You'll like it.

 

[Supersubes]

Neck turning is just another step that isn't needed in a tactical rifle. Not to mention the process of neck turning is one of the more unpleasant procedures in BR loading. All of my 6.5's have .295 necks, and my loaded rounds are in the realm of .290"-.291" from memory. Shooting a tight necked tactical rifle will probably cause your gun to stop at some point, or at the very least a bad flyer. Regarding brass life, what do you consider vastly improved? I'm at 20 firings on my 6.5x47, and I haven't culled a single case due to a split neck, and i see no reason why these cases wont go many many more firings. My working lot of brass for that barrel is 200 cases. The key there IMO is annealing, which is much simpler than neck turning. Annealing also makes for very consistent neck tension, which lowers velocity spreads drastically.

With my .260 brass(Win 7-08 or Rem .260), the limiting factor for my brass life is primer pockets loosening. I can't recall the last time i split a neck.

Also, I dont uniform pockets or flash holes, sort brass for weight, clean pockets between firings, and I throw charges from a harrell's measure 50 rounds at a time with no weighing in between. I use a custom Neil Jones FL sizer for the 6.5L, and I FL size with all calibers without exception.


Here is the same rifle that fired the above target(AIAW), but with the current .260 broughton on it. The lines indicate the extremes (up, down, left, and right). The box drawn at the top(also the lowest shot), shows the width and height of all 20 shots as if they were overlaid on each other. These bulls are smaller than the above target. The actual group width/height is written center top of the target.


Practical field accuracy, not benchrest. I used to be all wrapped up in a BR style of reloading. I shot OK, but the moment I stopped worrying about the equipment(Loads, barrel cleaning, etc.), the better I shot. Aside from the fancy 6.5L die, I could load my ammo on a basic RCBS master loading kit.