Another 30-06 Loading question

[Fugowii]

In my never ending quest to use a cast boolit in my 30-06 I seem to have encountered another stumbling block. First the specifics:

Rifle: Rem 700
Caliber: 30-06
Brass: LC of varying dates
Boolit: Lyman 311291
COL: 3.115"
Powder: Accurate 5744
Load: 20.8 grains
Primers: Rem LR

Previously I had been using a heavier load (published by Accurate) of between 24.0 and 28 if I recall. The result of that experiment was the primers were flattening and backing out even at the min load of 24.0.

Anyway long story short. I loaded up ten rounds of LC brass at a COL of 3.115" where I had used a COL of 3.0" previously. The reason I did this was that accuracy was atrocious with the previous load along with the primer distortion. The chamber actually could have taken a COL a few thousands longer but I decided that I would at least go slowly before I ventured that close to the lands.

I took these to the range today, not caring really what the results of my shooting skills were, but to see how these reduced loads shot. The results are interesting. The loads were mild, very mild. So mild that I wished I had brought along my chrony to see what they were doing. I wasn't pleased with the performance of the load but the biggest surprise was when I examined the shot brass. The primers are bulging! My question: What could cause the primers to bulge? It sure wasn't the pressure generated by the load.

[pcarpenter]

I don't mean to insult your intelligence, but primers backing out and flattening are usually caused by two things: Brass that's sized too much to fill the chamber and loads that are too light.

Cases that don't fill the chamber allow the brass to move forward under firing pin impact and the primers to be punched out as pressure builds, and then "nail headed" as pressure in the case drives it back against the bolt face.

Any case can become a bit too short under firing pin impact....that is even an empty case with no powder charge can be sized slightly shorter due to the firing pin strike driving the case forward into the chamber as though it were a sizing die. It's an effect that is most prominent with slope-shouldered cartridges and the '06 probably qualifies.

Because I don't shoot 5744 in the '06, I am hesitant to start telling you what sort of charge would do the job to keep the brass against the bolt face, but if you do have data, you might want to work up from the minimum load a bit at a time. Greater chamber pressure will serve to hold the case against the bolt face. Too little charge can actually result in the case stretching from the head area instead of from the shoulder area as it should (stretching to fill the chamber).

Another thing you can do to help hold the case back is to seat the bullets into the lands just a bit. Cast bullets don't like "impacting" the lands anyway, and it should also serve to pin the case rearward during the initial part of the firing cycle. This is commonly done to help when fire forming cases, to insure that the stretching to fit comes from the front of the case.
Paul

[Fugowii]

I don't mean to insult your intelligence, but primers backing out and flattening are usually caused by two things: Brass that's sized too much to fill the chamber and loads that are too light.

Cases that don't fill the chamber allow the brass to move forward under firing pin impact and the primers to be punched out as pressure builds, and then "nail headed" as pressure in the case drives it back against the bolt face.

Any case can become a bit too short under firing pin impact....that is even an empty case with no powder charge can be sized slightly shorter due to the firing pin strike driving the case forward into the chamber as though it were a sizing die. It's an effect that is most prominent with slope-shouldered cartridges and the '06 probably qualifies.

Because I don't shoot 5744 in the '06, I am hesitant to start telling you what sort of charge would do the job to keep the brass against the bolt face, but if you do have data, you might want to work up from the minimum load a bit at a time. Greater chamber pressure will serve to hold the case against the bolt face. Too little charge can actually result in the case stretching from the head area instead of from the shoulder area as it should (stretching to fill the chamber).

Another thing you can do to help hold the case back is to seat the bullets into the lands just a bit. Cast bullets don't like "impacting" the lands anyway, and it should also serve to pin the case rearward during the initial part of the firing cycle. This is commonly done to help when fire forming cases, to insure that the stretching to fit comes from the front of the case.
Paul

This is interesting. I was under the impression that pressure was the primary cause of primers backing out and flattening. I would associate that with a hot load more than a soft load. As for sizing the case, I size according to the Dillon sizing die and a case gauge. I trim my cases to the "trim-to" recommendations. Am I missing something else that I am not aware of with respect to my case prep? The primers are not flattened. They have either bulged or backed out slightly. All of them did it to varying degrees.

[pcarpenter]

The ideal in a bolt gun is to just size the brass enough so the bolt just closes without resistance. I actually like to disassemble the bolt and use the bolt without the cocking resistance of the firing pin/cocking piece and establish the right sizing dimension for the chamber in that particular rifle. If you don't size brass for other guns with those dies, it's a one shot deal. The only rifles in which I shoot cast bullets are surplus rifles and they typically have over-dimension chambers, making it important to fit the brass and size it very little (so it will last).

In bolt actions I have with tight necks and tighter fitted cases, you do still get just a bit of resistance on closing with properly fitted brass that is once fired. The trouble with case gauges is that fitting the round to them will guarantee that they will fit in the chamber, but may result in more sizing than needed, reduced brass life, short rounds that let the primers back out etc.

Once you've fired those cases in that rifle one time....and especially with light cast bullet loads, you can then get by with only sizing maybe 2/3-3/4 of the neck and not touching the body of the case. This can be done with a neck-sizing die that doesn't even touch the rest of the case, or with a regular sizer, backed out quite a bit. Die spacer washers are a quick way to get to that point without messing with your die lock ring setting. Your brass will last a long time, be more accurate since it fits the chamber, and will not have stretching issues. In varmint rifles where I shoot jacketed stuff at higher velocities and pressures, I often have to full-length size maybe every 3-5 passes. At lower pressures where the elastic limit of the brass is not exceeded you could theoretically find that you can go a long time before you start feeling enough bolt resistance to cause you to need to full-length size again.

You mentioned the bulging primers....I've seen some of that too. The primer cup material is relatively soft and will yield under tens of thousands of pounds of pressure so (like the brass itself) it needs the support of the bolt face so brass fit and maybe a bit warmer load will help.

Typical high pressure signs include primer "cratering" where the primer starts to flow in around the firing pin and back into the firing pin hole in the bolt face. This looks like the pock-mark craters you see on the moon from asteroid impacts but on a microscopic level. If this is too bad you will get primer ruptures there too...and that's typically *way* too hot. Go far enough and the primer pockets in the brass stretch and won't hold a new primer....all pretty wicked signs that mean *back off*.


Paul

[Fugowii]

The ideal in a bolt gun is to just size the brass enough so the bolt just closes without resistance. I actually like to disassemble the bolt and use the bolt without the cocking resistance of the firing pin/cocking piece and establish the right sizing dimension for the chamber in that particular rifle. If you don't size brass for other guns with those dies, it's a one shot deal. The only rifles in which I shoot cast bullets are surplus rifles and they typically have over-dimension chambers, making it important to fit the brass and size it very little (so it will last).

In bolt actions I have with tight necks and tighter fitted cases, you do still get just a bit of resistance on closing with properly fitted brass that is once fired. The trouble with case gauges is that fitting the round to them will guarantee that they will fit in the chamber, but may result in more sizing than needed, reduced brass life, short rounds that let the primers back out etc.

Once you've fired those cases in that rifle one time....and especially with light cast bullet loads, you can then get by with only sizing maybe 2/3-3/4 of the neck and not touching the body of the case. This can be done with a neck-sizing die that doesn't even touch the rest of the case, or with a regular sizer, backed out quite a bit. Die spacer washers are a quick way to get to that point without messing with your die lock ring setting. Your brass will last a long time, be more accurate since it fits the chamber, and will not have stretching issues. In varmint rifles where I shoot jacketed stuff at higher velocities and pressures, I often have to full-length size maybe every 3-5 passes. At lower pressures where the elastic limit of the brass is not exceeded you could theoretically find that you can go a long time before you start feeling enough bolt resistance to cause you to need to full-length size again.

You mentioned the bulging primers....I've seen some of that too. The primer cup material is relatively soft and will yield under tens of thousands of pounds of pressure so (like the brass itself) it needs the support of the bolt face so brass fit and maybe a bit warmer load will help.

Typical high pressure signs include primer "cratering" where the primer starts to flow in around the firing pin and back into the firing pin hole in the bolt face. This looks like the pock-mark craters you see on the moon from asteroid impacts but on a microscopic level. If this is too bad you will get primer ruptures there too...and that's typically *way* too hot. Go far enough and the primer pockets in the brass stretch and won't hold a new primer....all pretty wicked signs that mean *back off*.


Paul

Wow! Good info. I think I have more questions but I need to think about what you've written. Thanks very much.

[smokeywolf]

This problem of the 30-06 case and others that head-space against the shoulder suffering primer setback or bulge is not uncommon. The sizing dies are bored or ground to size the brass for a minimum chamber size. This is one of the reasons for neck sizing only. The other issue to explore is the possibility that you may have some peening of your bolt face. Don't know about Remington 700s, but the old Winchester model '95s in 30-06 are notorious for that issue.

Also, I have read that following the firing pin striking the primer and driving the case forward against the shoulder (as pcarpenter stated) that the case pressure builds to "weld" the outside surface of the case against the chamber walls. This reduces the rearward thrust of the case head against the bolt face. I can see how this could allow the primer to be driven back.
pcarpenter, please chime in and correct me if I'm wrong.

smokeywolf

[geargnasher]

+1 on sizing the brass WAAAYYYYYY too much, you guys nailed it. Back the die off the shellplate until it just barely "kisses" the shoulder of brass fired only in this ONE rifle.

Gear

[Fugowii]

Do I need a dedicated neck sizing die to do the neck sizing or is it possible to use the standard sizing die to achieve this?

[462]

A conventional full-sizing die can be backed out to size the neck only. However, in my experience, the Lee collect neck sizing/decapping die does a better job. If you ignore Lee's directions, you can adjust the die so that it applies just the desired amount of neck tension.

[pcarpenter]

I have standard neck size dies for a few cartridges....usually came as part of a three die (Redding) set that also included a full-length die. I wouldn't particularly opt to do that again. If I am going to size the neck to "standard" dimensions, then just backing the standard sizer off (Often using a die spacer washer) gets the job done inexpensively and leaves part of the neck fitted to chamber dimensions.

I like the bushing-type neck sizer dies...especially now that I am shooting cast bullets in surplus rifles. This may be less of an issue for you with a more modern factory chamber, but the bushing type neck dies let you buy bushings that barely squeeze the neck enough to grip a bullet. That's often a lot less brass movement than you get with a standard die's neck dimensions. With cast bullets, often a factory neck dimension will end up sizing your bullet base down....something you really don't want. I have an 8x57 Mauser or two that have fired case neck dimensions so large that to get a "just enough" grip on a cast bullet, I'd need a neck bushing they don't even make. I ended up making a bushing in that case.

I only have one of the Lee collet type neck dies (in .270Win) and it does indeed seem to work fine. I have read where you can make yourself a larger mandrel for the Lee collet die (part the collet squeezes against"), in order to accomplish the minimal sizing I was talking about above. I may give that a try for a cartridge or two where I lack a bushing type neck die since the Lee collet dies are certainly cheaper.

Edit-- smokeywolf....re. the brass "grabbing" the chamber walls ....never heard of actually "welding" it to the walls, but it surely does grab as the pressures inside the case expand it outward, and then allows the case to stretch from the wrong end. I didn't do a very good job of conveying this in an earlier post but that was what I was driving at with regard to brass stretching from the wrong spot (the case web area) rather than blowing out from the shoulder area. I have a couple of Lee-Enfields with oversize chambers and I actually slightly lube the cases with Imperial sizing wax at shooting time, in order to get them to slide back and touch the bolt face. This is done on the first firing to get the brass to stretch to fill the oversize chamber, from the *shoulder* area rather than from the web. The loads are no where near hot, so it's certainly not going to cause any excessive bolt thrust in that case. After that, I just size enough to close the bolt with ease. So....tying this back to the OP....there's a case where properly fitted brass would never fit in a case gauge.
Paul

[Harter66]

I've 3 ,30-06's. None of the 3 will share brass . 1 is generally oversized, 1 just has a fat shoulder, and the 3rd won't even feed the brass back in that came out . My answer is 2 sizing dies , 1 is set to full length size for range. Brass and the 3rd rifle . The other has been neck lapped and fitted w/new expanders for the other 2 and set up to just touch the largest case shoulders. Which is only about half the neck. So far so good.

[geargnasher]

Do I need a dedicated neck sizing die to do the neck sizing or is it possible to use the standard sizing die to achieve this?

See post #7.

Gear

[Fugowii]

See post #7.

Gear

Thanks. Overlooked that post.

[fatnhappy]

Fugowii,

First and most important..... That brass most likely has been set back far enough that it might cause case head separation with heavy jacketed loads. Mark it with a sharpie and use it exclusively for CB use.

Like Pcarpenter said, an easy way to confirm the 24 grain load is safe in your rifle is to prevent forward movement of the brass by seating your bullet far enough out to offer resistance closing the bolt. That might not be as easy as it sounds if your 311291 has a typically undersized nose so I would suggest trying a heavier boolit such as a 311284 or 314299.

[David2011]

What Gear said. Any time the chamber is larger than the brass the primer will back out. If the load is light it stays backed out. With full charges the case is pressed back down over the primer. If the load is hot enough, THEN the primer will anvil out after it is reseated by pressure.

David

[Fugowii]

OK, got the neck sizer ready to go but in the meantime I have another problem.

Seating Dies & Cast Boolits Problem

I have a problem trying to get a consistent seating depth on my 30-06 cases with a 311291 boolit. I load on a Dillon 550 and it is a Dillon seating die. I'm trying to get a 3.115" COL and it will seat anywhere between 3.100" and 3.125". The boolits are all from the same mold and cast with the same alloy. The cases are all of the same length and are LC. I have also tried this with a RCBS seating die as well and the results are similar. Anyone else ever have this problem? Any suggestions would be helpful and much appreciated.

Here are four I just did after going over the die adjustment according to the Mfg instructions and making sure I wasn't messing up:

3.102"
3.107"
3.109"
3.1145

The seating die insert on both the Dillon and the RCBS mates with the head of the boolit about a 1/4" from the tip as I can see a fine line around the boolit at that point. I'm wondering if, unlike a more pointed jacket bullet which would fit into the seating plug taper, if this is my problem? Having the seating depth controlled by a small engaging surface might be problematic? The opening on the seating plug is too small to allow the boolit to enter it more than what I have indicated.

[leadman]

I know RCBS will supply you with a different bullet seater stem that will work better. Don't know if Dillon will but probably.
The 311291 was originally designed for the 30-30 so if you ask for a seater stem for that cartridge as I did it should work well.
If you can't get a seater you can make your current seater fit by using JB Weld to form a new seater. Clean the seater of all lube, etc., and install it in the die. Put a little bullet or case lube on the tip of the boolit in a case. Mix the JB and put it in the seater and then lower the seater to the boolit tip with slight pressure. It will have to set up for 4 or so hours so if you don't want to hold on to the press handle that long find a way to make it stay in position.

[Fugowii]

I know RCBS will supply you with a different bullet seater stem that will work better. Don't know if Dillon will but probably.
The 311291 was originally designed for the 30-30 so if you ask for a seater stem for that cartridge as I did it should work well.
If you can't get a seater you can make your current seater fit by using JB Weld to form a new seater. Clean the seater of all lube, etc., and install it in the die. Put a little bullet or case lube on the tip of the boolit in a case. Mix the JB and put it in the seater and then lower the seater to the boolit tip with slight pressure. It will have to set up for 4 or so hours so if you don't want to hold on to the press handle that long find a way to make it stay in position.

Thanks leadman,

I called Dillon and that is a no-go but I did get an additional seating stem so your fix for my problem sounds like a winner. I also emailed RCBS and inquired about a different seating stem, but I haven't heard back yet. Thanks very much for the help!

[Fugowii]

I know RCBS will supply you with a different bullet seater stem that will work better. Don't know if Dillon will but probably.
The 311291 was originally designed for the 30-30 so if you ask for a seater stem for that cartridge as I did it should work well.
If you can't get a seater you can make your current seater fit by using JB Weld to form a new seater. Clean the seater of all lube, etc., and install it in the die. Put a little bullet or case lube on the tip of the boolit in a case. Mix the JB and put it in the seater and then lower the seater to the boolit tip with slight pressure. It will have to set up for 4 or so hours so if you don't want to hold on to the press handle that long find a way to make it stay in position.

I think I have fixed my problem. The Dillon seating stem has a hole drilled in it and I ran a 10-32 MF tap the length of the hole and inserted a 10-32 screw in it. I adjusted the screw length by inserting the 311291 boolit at the end of the seating stem and brought the screw down to kiss the tip of the boolit when the boolit was resting on the outer lips of the stem. I just ran four test seatings on it and the length came out +/- .001". Here are a couple of pics. I will put a lock nut on the 10-32 screw eventually but it's a good snug fit at this time.

http://i73.photobucket.com/albums/i227/BP_2006/08_11_2012003a.jpg http://i73.photobucket.com/albums/i227/BP_2006/08_11_2012002a.jpg