Yes, every charge was hand weighed and checked with two different digital scales. I don't have a balance beam scale but the two digital scales agreed exactly. I was using a Franklin Arsenal Intellidropper to dispense the powder and then checked it with another digital scale.
Blown out primers and pressure signs
- Thread starter mikehill85
- Start date
The neck tension is 0.002" inches.
I used both Lapua and Hornady but not mixed together. I was getting blown out primers and pressure signs with Lapua, so I tried Hornady instead because it has a higher H2O capacity. I got the same random blown primers and pressure with Hornady.
In that case, start from the beginning. Not all barrels/cambering are the same. I'd start at the MINIMUM charge shown in a reloading manual for your powder AND bullet you're using, verify charge weight with both scales, seat bullets at least 20k OFF the lands. Make 3 rounds for each charge increasing in .3g increments. You'll find your best/most accurate charge. Not fastest, not hottest, just best. Use the same components in all rounds. Seems very basic but, basic works and won't get you hurt.
To "start from the beginning" for me is running a pressure test.
That is, loading just 1 round each with increments from low to high, and when I see pressure signs I've got a good idea where the limit is for running load development charges. I leaned my lesson a long time ago when I loaded up some charges that seemed like they should be safe, according to published data and what people were using, but it turn out with pressure signs right off the bat. So, now before I do any load development, I do a quick pressure test.
It looks like we may have found the problem. I tried pushing an inert cartridge of the 147 grain ELD-Ms in with finger pressure, the bullet was seated to what I thought was 0.020" off the lands but it didn't drop out under its own weight. Even bumping the butt of the rifle didn't dislodge it. I had to push it out with a cleaning rod. I am going to thoroughly clean the rifle and try the test again, but this is promising.
jxb
Gold $$ Contributor
I shoot similar to this except once fired Norma and at 42.5 ~2650fps; 43.2 ~2720 with pressure starting well above that (around max book). I always work up to pressure so I know where it starts and also where case changes and how much. (Norma once fired, Fed 210, 143 eld-x, 6.5 staball)
Assuming all your case prep specs check out, you might simply match factory CBTO and see what you get. I know on my Tikka 6.5 touch is not far out from the factory Norma 143 match I started with. 0.085 might not seem like a lot unless those factory are already long ;-)
=====================================
Primer: Federal 210M
Brass: Lapua LRP
Bullet: 143 grain Hornady ELD-X
Powder: 6.5 Staball
Charge: 42.5 gr (max is 43.5)
CBTO: 2.2520"
Velocity: 2,717 fps
I measured some factory ammo:
Hornady Precision Hunter (143 grain ELD-X bullet).
CBTO: 2.1677"
Base-To-Shoulder: 1.5315"
Assuming all your case prep specs check out, you might simply match factory CBTO and see what you get. I know on my Tikka 6.5 touch is not far out from the factory Norma 143 match I started with. 0.085 might not seem like a lot unless those factory are already long ;-)
=====================================
Primer: Federal 210M
Brass: Lapua LRP
Bullet: 143 grain Hornady ELD-X
Powder: 6.5 Staball
Charge: 42.5 gr (max is 43.5)
CBTO: 2.2520"
Velocity: 2,717 fps
I measured some factory ammo:
Hornady Precision Hunter (143 grain ELD-X bullet).
CBTO: 2.1677"
Base-To-Shoulder: 1.5315"
I bought a Hornady OAL gauge thinking it would be faster. It now sits on the bench unused. I was getting to inconsistent measurements to feel comfortable. I do use a Hornady comparator and I use it just as it is intended. To compare my own measurements and as a set point to my own achieved measurements.
Unless you have an extended throat , the hornady 147s' are WAY too long for a 6.5 creed . The shank of the bullet plunges well past the neck shoulder junction . So if you are getting dough nuts there is a source for pressure . To stay at mag length and above the dough nut Berger 130s' and Sierra 130s' are what to use . Then start with what you know by using a mic and measure new ,fired, and sized cases against each other . On the base and shoulder dia measure to the tenth .
dellet
Gold $$ Contributor
This can happen by user error, not being able to feel when the touches. It takes time to develop that “feel”. Sometimes it’s compounded if the bullet won’t slide out of the case freely. It has to fall out.
Using a case that was not fired in your chamber. That’s why checking the base to shoulder on the Hornady modified case is important. If that is longer than your sized brass, your brass automatically sets the bullet deeper into the chamber.
Your chamber might be a bit tight, but I think you found your problem. It’s likely that some of your bullets Jammed deeper than others, there’s your random spikes.
Looking forward to a range report.
You’re not the first and won’t be the last to fall victim to that tool.
searcher
Gold $$ Contributor
This is a very valid statement. I have a few barrels (in factory rifles) that will not tolerate certain upper-end loads in some manuals. I assume you are measuring your shoulder position (as measured from shoulder to base) both after sizing AND after bullet seating? Excessive force encountered when seating bullets (sometimes a bit hard to detect - depending on softness of brass) can push to shoulder back, giving you excessive clearance, as though you had bumped the shoulder too much. Because you have encountered this high pressure situation when full-length sizing or neck sizing only, and with multiple brands of brass, you have eliminated a lot of possibilities. Your question of not bumping enough is likely "no". Typically, one can allow a shoulder to move forward to the point the bolt signals resistance when it is closed (bolt gun). When that occurs, you tend to simply have difficult to chamber brass. While that is not desirable, beyond just feeling contact when the bolt closes, firing such a round typically does not increase pressure. Having excessive "headspace" (on your brass) CAN cause symptoms of high pressure, usually flattened primers - but blown primers will eventually occur when there is enough clearance present to allow the primer to bet blown out (which is less than the height of the primer!). Since you have gone through different brands of brass and primers with the same results, these types of problems are usually from using too long of trim length, excessive shoulder clearance (on your brass) or too hot of a load for your particular barrel - and how the chamber was cut can often have nothing to do with it - other than adjusting the published trim length and the need to find the proper bump for that chamber. You might want to consider the purchase of an "ammo checker" which you can use to verify whether your loaded ammo will fit into it. Being a factory rifle, you should have ammo that will fit the checker. if it doesn't, it might help you to determine why. Even if the ammo slips right in - that does not mean you don't have excessive shoulder clearance. Somebody (I forget who) makes or used to make a dummy cartridge that was adjustable in length so one can make rather accurate length measurements of their chamber and apply it to their loaded ammo. Good luck!
Yup, that sounds like the problem as touching or jamming the lands that way increases max start pressure by almost 8k psi.
So I thoroughly cleaned the gun and the inert cartridge still stuck. I had to seat WAY WAY back (0.128"!) until I got close to the COAL listed in the reloading manual before it would drop free under its own weight. I'm going let the gun sit muzzle down overnight to make sure all the cleaning solvents are out and try again tomorrow. Maybe some moisture was causing the cartridge to stick. I just find it hard to believe the Hornady reloading tool could have caused the measurement to be that far off.
Any other suggestions on how to measure the distance to the lands would be appreciated. I did try pulling the ejector and firing pin spring and seeing if the bolt would close under the weight of the handle with both an inert cartridge with my old "0.020" off the lands" measurement and the one that dropped free. It didn't close on the old one and it does on the one that dropped free.
I sometimes use a cleaning rod fitted with two stop collars. Close bolt on empty chamber leaving it cocked. Insert rod and lock down first collar. Remove bolt, drop in bullet, insert rod and lock down second collar. Measure between the insides of the collar.
I will add that with some bullets I use a wooden dowel and push lightly on base of bullet feeling the contact point while holding the rod in the other hand.
Results Depend on bullet ogive. I just recently struggled to get good repeatable readings with VMAX in a 6 bra.
Results Depend on bullet ogive. I just recently struggled to get good repeatable readings with VMAX in a 6 bra.
Hmmm??? I know that technique is used to establish the proper headspace (particularly when installing a new barrel), but I hadn't heard of it being used to touching the lands (sounds like a lot of work to do it that way???).
To find where the lands is, I simply use the Hornady's OAL gauge using a bullet from the particular lot I'm using. I'll set the bullet in the case that's on the gauge, lock the shaft down with its screw, then shove it tightly into the chamber to make good contact on the shoulder. Holding it firmly against the shoulder, I loosen the screw and lightly tap the shaft to move the bullet lightly against the lands, then gently holding it there, I tighten the screw to keep the shaft in place. When I remove the gauge, and get the bullet to fall out, I insert the bullet back into the gauge and take a measurement. So, this how I find and measure where the lands is and get pretty consistent results. I do this 3 or 4 times to verify the measurement I'm getting and it takes about 5 minutes all together.
Lock‑N‑Load® O.A.L. Gauges & Modified Cases - Hornady Manufacturing, Inc
Lock-N-Load® O.A.L. Gauges Regulating seating depth and the resulting jump to the rifling is widely regarded as fundamental to improved accuracy. A few thousandths of an inch change between the bullet and the rifling can make the difference betw...
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Murray Brook
Silver $$ Contributor
Use a dummy round with the bullet colored with a black felt marker. Chamber the round and check the bullet for rifling marks. If yes color again and seat the bullet slightly deeper and recheck for rifling marks after chambering the round. Repeat this process till the rifling marks just disappear. Will give you a fairly good idea of where the lands begin with a certain bullet.
dellet
Gold $$ Contributor
There’s lots of ways to confirm, you can color the nose of the bullet to make it easier to see when they touch the lands. The bolt drop method is fine.
I’d probably start with someone like @338 Mollett who has loaded that combination and has some direct insights. See post #50
But bottom line is if the bullet or cartridge won’t fall out, it’s more than a touch. And depending on how your chamber is cut, and shoulder placed, I’d expect to possibly start touching at 2.140” base to ogive. Because according to the SAAMI drawing that’s where the lands can start
I’d probably start with someone like @338 Mollett who has loaded that combination and has some direct insights. See post #50
But bottom line is if the bullet or cartridge won’t fall out, it’s more than a touch. And depending on how your chamber is cut, and shoulder placed, I’d expect to possibly start touching at 2.140” base to ogive. Because according to the SAAMI drawing that’s where the lands can start
DLT
Silver $$ Contributor
I use a loaded round or can be a full length sized and bullet seated. I insert the round into the action and push the round into the chamber with my pinky. If it doesn’t fall out, tap it out with a cleaning rod and seat the bullet deeper. Their bullet comparator tool is good for measuring this. Repeat the process till it no longer stays in the chamber
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