Must use faster or slower propellant?

[spitballer]

Continued trials and failures have convinced me that I'm definitely not going to be able to use Varget in my .223 bolt rifle for 64 grain Berger varmint bullets. This morning I loaded up a conservative 24.4 grains and right away I ended up with a pierced primer and a mushroomed case that had to be dremeled off the bolt, a process I'd rather not repeat. velocity was 3095, CCI#400, Nosler case, 30"bbl

Apparently I'm at a point where I have to use either:

1) a faster powder that doesn't build up so much pressure
or
2) a slower powder that doesn't build up so much pressure


I can't explain the dynamics of this paradox, but the bottom line is I seem to have found a point where I'm going to have to use either a faster or a slower powder. For accuracy I'd like to go with a faster powder if possible, even though this seems counterintuitive. I have some BL(C)-2 on hand - has anyone used BL(C)-2 successfully with a heavy bullet such as the 64? Thanks in advance, not trying to put anyone out on a limb here but I've got to work with this 30' bbl

 

[Blue68f100]

Your at the low end of the load range. Sounds like your into the lands to run the pressure up as high as what your getting. What OAL are you using? Mark up a bullet and case to see where your contacting at.

I've used Varget with great success with 65gr and 69gr bullets by sierra. I have not used Berger bullets to know how their length run in relations to Sierra. As for powders I've used with sucess would be TAC, CFE-223. I could not get the H335 to shoot accurately in any of my guns.

 

[ponchh]

Your way out of my league with the 30" barrel but I am using 24.5 varget with a 68gr match. Maybe back off on oal a little and see what happens.

 

[Dudedog]

Probably not the most accurate powder for a bolt gun but I had good results with BLC(2) in my AR and Mini 14 with 62gr bullets. Meters well.
Since you have some I would say try it, but don't think a powder change alone is the answer to your issue.
I would double check your case lengths, OAl etc. Might be a good idea to verify the scale with some check weights if you haven't already,
since you said you don't want to repeat the fun with the Dremel.
As always start low and work up.

BLC(2) is just a hair slower than Varget according to a couple burn rate charts
#104 vs 101 on one chart, 102 vs 99 on another, of course charts don't tell the whole story.

 

[243winxb]

Polygonal rifling. How i see it.

This type provides excess bullet bearing surface contact. More of the bullet is in contact with the bore then standard rifling.
This extra friction greatly increases pressue. Normal load data can not be used. Maximum pressure is maximum pressure. Doesn't matter if the powder burn rate is fast or slow, when using normal data for the 223.

Look at the Hodgdon load data for 223, 55 GR. BAR TSX FB, and Varget. This Barnes bullet has a longer bearing surface then normal lead core bullets. It also is of a different harder construction. 100% Copper. Notice how much less powder is used, compared to other heavier bullets.

Your polygonal rifling has the same effect.

A Barrel length of 30" may produce less velocity then a shorter barrel. Excess friction would be the cause.

I see you have many posts on this rifle. I feel you just dont get it. Sorry

What you are doing is not safe.

 

[ArchAngelCD]

It does sound like a pressure problem caused by something other than the powder. That light a charge if Varget should not be causing this problem. Is the bullet into the rifling? What OAL are you using?

 

[redbullitt]

A bit of perspective that may help from a similar loading situation...

When I shoot my 458 socom I use a few different bullets. One is a 325 hornady, standard jacketed lead core. The other is a 300g barnes, solid copper. That 300g barnes is lighter, but it takes quite a bit less powder to show pressure signs. YMMV, but you might be seeing the same thing.

Varget tends to work very well in 223 as far as I know, so I think you might indeed have something else going on to cause those problems.

 

[243winxb]

The polygonal rifling has more contact with the bullet then standard rifling.

A gun barrel according to claim 2 wherein the groove diameter is about 0.224 inches, the bore diameter is about 0.219 inches and the flat diameter is about 0.215 inches.

The .215" diameter would build more pressure, if the "flat" covered more area then normal lands.

No expert here. Just my reasoning as to what is causing the high pressure.
https://www.google.com/patents/US20120180362

 

[spitballer]

Thanks to all for your concerned responses.

- 243winxb you're right on the money with this one, I'm afraid. Yes, I'm still struggling with that same polygonal barrel and there's no question that I'm getting a lot of friction. Apparently what is happening is that friction is making the expanding plasma more dense and unforgiving, especially with certain propellants.

After reading these posts about start pressure I'm beginning to think my best bet is going to be to stay with a slower propellant to solve this one. Admittedly I've had some success using H414, with tightest groups between 28 and 28 1/2grains, but it's just not as accurate as I'd like. Maybe I'm just being a perfectionist.

When the bore was new and rough I could get consistent 1/2 moa groups with 55 grain bullets at 26.7 grains of H414, traveling around 3025 fps. But after break-in I couldn't keep the velocity down, even with wadding. I wonder if I were to stick with the same 26.7 grains of H414 and simply use the weight of a heavier 64 grain bullet to keep it around 3025 fps - this is what I'm mulling over at the moment.

The perspective from multiple responses is valuable and I'm going to agree that I've simply got too much start pressure. Whether this is from seating into the lands, or powder selection, or even the properties of the primer used with stick powder I don't know, but it would seem that in this instance I would be safer on the slower side with propellant and primer. Safety has to come first, I found that out. Thanks again to valued members.

 

[Rule3]

Have you listed your COL anywhere??

Perhaps call Berger?

Do you have their manual??

http://www.bergerbullets.com/contact-us/

 

[spitballer]

Dudedog, ponchh, ArchAngelCD, Rule 3 - about OAL I haven't kept tabs on OAL since converting action to single shot. The only difference I've seen by seating bullets into the lands has been the ability to reduce the powder charge by about a half grain or so, using thin-jacketed bullets. The berger jacketing on the 64 seems to be a little harder than the nosler but it's still thin, and a far cry from a FMJ which I would be very hesitant to seat into the lands.

Offhand it just seems to me that a 64 grain, .224 bullet in a 12" twist barrel has no business traveling any faster than 3000 fps or so, regardless of barrel length and this is why this whole thing doesn't sit well with me.

Yes I can run 28-28.5 grains of H414 safely with the 64's, but the velocity is alarming and they don't tighten up like they should. My feeling at this point is that if I can reduce the charge of H414 to slow the bullet down to a more appropriate velocity and still maintain friction I may have the ticket for a good load. My sense is that the propellant is going to be constant and unforgiving and that if I want to increase [obturation] at a given velocity in the absence of proper friction my options are pretty much limited to changes in bullet weight unless I can make adjustments to give higher pressure at the start, a tricky business.

Thanks again to members for valued perspective.

 

[Dudedog]

Usually you can find a couple nodes where a barrel shoots well. Just depends. For fun pick your powder and back all the way off to start or maybe a little lower and go up .3 at a time towards MAX and see what you find.
Might sacrifice a little velocity but unless you really need it for a reason I generally don't mind giving up a little bit for a more accurate load. Also since you are skirting with pressure issues that might let you find a node at a lower pressure.
Maybe something there maybe not.

Only need enough friction to spin the bullet?? Less friction is generally a good thing...think moly coated bullets.
I would think at normal rifle pressure 1000-3000 PSI is not going to make much difference in obturation, might for pierced primers however. But I spend more time loading pistol, so the rifle guys are probably more help here than I am.

If the barrel just does not want to cooperate, maybe time for a new barrel? Expensive but cheaper than a trip to the ER due to something bad happening from excess pressure.

 

[Toprudder]

Look at the Hodgdon load data for 223, 55 GR. BAR TSX FB, and Varget. This Barnes bullet has a longer bearing surface then normal lead core bullets. It also is of a different harder construction. 100% Copper. Notice how much less powder is used, compared to other heavier bullets.

Being an all-copper bullet, it is less dense than a lead core bullet, so for the same weight it MUST be longer. More of the bullet will be inside the case and will reduce internal volume, also contributing to the lower charge.

 

[Rule3]

Dudedog, ponchh, ArchAngelCD, Rule 3 - about OAL I haven't kept tabs on OAL since converting action to single shot. The only difference I've seen by seating bullets into the lands has been the ability to reduce the powder charge by about a half grain or so, using thin-jacketed bullets. The berger jacketing on the 64 seems to be a little harder than the nosler but it's still thin, and a far cry from a FMJ which I would be very hesitant to seat into the lands.

Offhand it just seems to me that a 64 grain, .224 bullet in a 12" twist barrel has no business traveling any faster than 3000 fps or so, regardless of barrel length and this is why this whole thing doesn't sit well with me.

Yes I can run 28-28.5 grains of H414 safely with the 64's, but the velocity is alarming and they don't tighten up like they should. My feeling at this point is that if I can reduce the charge of H414 to slow the bullet down to a more appropriate velocity and still maintain friction I may have the ticket for a good load. My sense is that the propellant is going to be constant and unforgiving and that if I want to increase [obturation] at a given velocity in the absence of proper friction my options are pretty much limited to changes in bullet weight unless I can make adjustments to give higher pressure at the start, a tricky business.

Thanks again to members for valued perspective.

HUH?? How do you load without knowing what the COL is??

Well, to me, without knowing if the bullet is "jammed" into the lands then it is impossible to determine what the issue is.???

"By the manual" your charge is not excessive so what causes over pressure?????????

roseanne roseannadanna it's always something

 

[spitballer]

For consistency and simplicity I've always loaded into the lands but then, I've always used soft, thin jacketed bullets. I knew I wouldn't be using FMJ's so I ordered the lands as close as possible, and when the bbl was new I could even seat 40 grain boat tails into the lands. Even so, rule3 I don't think OAL is going to be the issue when I'm seating out as far as possible not in as far as possible, I mean... yes a 64 is big for .223 case but the bergers are so darned skinny they don't push into the case that far. Rather than trying for a specific OAL it's easier for me to just get the necks consistent and load .010" over. Obviously it needs to be checked with every new box but this system seems to be pretty foolproof.

WinXB and toprudder have touched on the only other variable I can think of that can make a difference and that hasn't been brought up yet, and that's bullet hardness. I'm not so sure a harder bullet would be the answer but there's the option of going softer - this may actually be one instance in which a cast bullet can be used to good effect. But implementing this idea could be complicated by the undersized neck - I don't know what kind of tolerances are involved as far as bullet sizing is concerned. Then of course there'd be the gas checks...

 

[Rule3]

It is better to load just "off the lands" than INTO the lands. The bullet jams up on start and pressure builds.

Start with the simplest things first.

Occam's Razor

Whatever

 

[spitballer]

Never occurred to me since berger recommends touching the lands and to me a single shot is 'simplest' for these fine projectiles. An undersized neck minimizes slop and blowby/erosion too IMHO although I've still had to adjust OAL from time to time. Nevertheless I agree rule3, simpler better and surely not in any hurry to tackle something like cast that's for sure

 

[243winxb]

undersized neck

Is this a "tight neck" that may require neck turning?

 

[Rule3]

What exactly is "loading to the lands" doing for you? Are you achieving one hole groups a 500 yards?? Or is it a source of over pressure and pierced primers?

Is you brass all trimmed to length?

Yes, one can seat to the lands but it depends on the rifle and bullet. If by chance you have Hornady # 8 read pages 13 through 28 it explains, head space, case length and seating the bullet out to the lands and how pressure can increase dramatically and cause the issues you are having.

As others mentioned I doubt it is the powder, The difference between Varget and BLc is insignificant,

Adjusting the COL is a simple thing to do and try.

 

[ATLDave]

Berger makes both tangent and secant ogive bullets. IIRC, their view (or at least the view of their chief ballistician/engineer) is that the secant ogive bullets (the ones designed for very long range shooting) are very sensitive to seating depth and that shooters may have to put a lot of effort into figuring out the right jump, if any, for those. I don't think the varmint bullets are secant ogive. This suggests that, per Berger's guy's views, they should be a bit less sensitive to seating depth in terms of accuracy... so maybe don't feel like you have to jam the lands.

 

[Blue68f100]

I have not seen any published load data books that recommend seating the bullet into the lands. They all publish recommended OAL and that is where you should start unless you have very tight chamber. And for those you may have to shorten to keep out of the lands. I have a min spec match chamber and there are several bullets that I use will seat me 0.020" into the lands. For these I shortened the AOL so I have a 0.020" jump and reduced the load and worked up use the then shorter OAL.

 

[spitballer]

Obviously it's startling to hear of such pressure from a minimal load of varget, but despite extenuating circumstances like the thinner cup of a regular CCI #400 primer and seating to touch the lands it's just as obvious to me that the larger issue here is prudent powder selection when working with a barrel that's significantly longer than a 24" test barrel.

With all due respect, seating a few thousandths off the lands isn't going to be especially helpful to the young new owner of a savage.223 target rifle with a 30" bbl who's made an imprudent propellant selection. Published load data is extremely valuable, and a lot of work and sweat has gone into these tables, but I found out the hard way that when you get into over-length barrels all bets are off - some of these propellants can really pack a wallop if they're given enough running room. There are those of us who still use old fashioned long rifles and FWIW I just hope we're not obscuring the very real issues associated with reloading for them.

 

[ATLDave]

So your theory is that this same load would not show pressure signs if you cut off 6" of barrel?

 

[spitballer]

Yes, If I faithfully recreated the conditions set forth in the load data, and this is why the tables are so valuable as a go-to reference. Admittedly this probably also means seating OFF the lands, even though there doesn't seem to be published specifications in this regard. My guess is .030"?

 

[ATLDave]

Peak pressure is reached in the first few inches of bullet travel or sooner. I do not see how barrel length - as opposed to some other factor - is giving you pressure signs.