6.5CM Load Dev Pressure Signs Help

[bornhunter04]

So was testing some loads again last night with my 6.5CM. I shot these same loads this past Saturday but wanted to re-verify before i loaded up a bunch of them.

The only variable that changed was i used 1x fired FL re-sized brass with a .288 neck bushing trimmed to 1.910".

The loads are as such.
130gr Berger VLD Hunting
New factory brass
My go to load is 42.4gr of H4350 (these are colored red/blue in the pictures)
I've tried 42.8 but they didn't shoot near as well so I've been looking for the next node.

New loads are:
New factory brass
43.2gr of H4350
43.6gr of H4350

These showed a lot of promise on Saturday with zero pressure signs at about 50*F.
It was 32*F last night.

When I loaded the new test rounds used the same bullets from the same lot. Checked the first couple for COAL and they measured out at 2.800. Stuck the bullet comparator on, and they measured at 2.158 at the ogive.

Now, my gunsmith measured the bergers for me and jammed all the way in the rifling gets me a COAL 2.870 so with a COAL of 2.80 they shoudl be jumping about .070".

Rechecked the new loads last night and they measured between 2.810 and 2.817 this was across 9 rounds.
Rechecked the ogive and still measured at 2.158, checked my go to load of 42.4gr and they measure at 2.150/2.151

So obviously the new loads are seated about .007-.009" longer than my normal load. This shouldn't put them into the rifling, but is it possible that it did?

When I loaded these up, i made another charge up and put it in a small sealed plastic container as a control for checking future loads if they shot well. Put it on my digital scale and they weighed in at 43.9/44.0gr. So I'm thinking my 505 scale might have been off when i charged these loads. But even at that, if it was in fact .3/.4gr high, the lower load of 43.2 should have been 43.5/43.6 which shot fine on Saturday with zero pressure signs.

Pictures:
This is my normal 42.4gr load


This is 43.2gr



All the brass, the one in the middle is 43.6gr



The brass grew about .025" after firing.
Also note the circle around the case.




Same thing with 43.6gr


So my questions are as follows:
Could having the bullet seated .007-.009" out be putting the bullets into the rifling even though the measured COAL was 2.870 jammed and these longer rounds measured at 2.817 at the longest?

Would the FL re-sized brass with a .288 neck bushing increase neck tension enough to increase pressure to the point to cause the pressure signs?

Also measured the brass from my 42.4gr load after firing and they come out to 1.919", so what would cause the brass with the new loads to grow .025"?

If my scale was off, that's one thing that can be corrected, but is there anything i might have been doing to cause a severe increase in pressure?

Note, No sticky bolt on 43.2gr load, just extremely flat primers and that ring around the brass. 43.6gr did get me sticky bolt and the same flat primer and ring around the brass.

I'd already tumbled the brass from Saturday, so i can't take pictures of them. They might have had some very faint primer flattening but no other pressure signs.

Also, measured the loaded rounds and the diameter of the neck was .295 which is to spec on via the hornady manual.

Thanks in advance for the help.

 

[thespecialist]

How far did you bump the shoulders back when you sized the fired brass?

 

[bornhunter04]

Don't have that measurement. Brass was FL re-sized same as I've always done. Used 1x fired brass with 140gr amax no problems. First time I've ever encountered an issue.

 

[flashhole]

I had a long drawn out post but it was devoured by the cyber gremlins.

Those flat primers are definitely a sign of high pressure. The next step up the pressure ladder is sticky bolt lift/extraction and you don't want that.

Unless you are using a roll crimp you will not get too much "neck tension". Even then the brass is soft enough to not create excessive pressure. If your chamber pinches the brass due to possible malforming of the brass/bullet when seating/crimping that could easily cause a problem. Best not to crimp. Your .288 neck bushing will not create an over pressure situation.

Check your scale. Make sure the balance arm moves freely and doesn't drag on the sides of the readout. Examine the pivot rod mechanism and make sure there is no debris in it. A drop of oil will help it.

I don't like the ring in the picture. If your brass is truly growing .025" (twenty-five thousandths) it means your headspace is excessive. When you FL size brass just bump the shoulder back .002". That will allow easy chambering and not overwork the brass. Get a paper clip and make it straight then bend a small angle at one end. You can use it to drag along the inside of the case to detect anomalies in the thickness of the brass. You will be surprised how easy it is to detect a thinned area. If you feel something you should retire the brass because it will separate, just a question of when.

 

[JB02]

You need to get some headspace comparators for your OAL gauge. You should be bumping the shoulder back ~ 0.002".

Your load is really hot, which is why you're getting so many pressure signs. If I was you, I would look at the next lower node, perhaps ~ 1.6 grains from where you are now.

 

[bornhunter04]

You need to get some headspace comparators for your OAL gauge. You should be bumping the shoulder back ~ 0.002".

Your load is really hot, which is why you're getting so many pressure signs. If I was you, I would look at the next lower node, perhaps ~ 1.6 grains from where you are now.

I've got a set, but not before i re-sized the brass i used. I'm going to take even more measurements and re-size some brass tonight.

 

[bjay]

Loded round is .295 i think 288 bushing is litle too tight im using 292.. you should stay below 43gr my load is 42.8 and it shots great no preasure signs at all

 

[flashhole]

bjay, help me understand your comment about the bushing being too tight. Brass has a specific ductility that defines its ability to tension the bullet in the neck. If the bushing is too small it may cause difficulty seating the bullet but I'm struggling to see how it will provide significantly greater neck tension once expanded. Not poking at you, just trying to understand. Work hardened brass may be a bit different as it tends to have more spring-back but that would be realized in less neck tension, not more neck tension because you are down-sizing the brass.

 

[bjay]

bjay, help me understand your comment about the bushing being too tight. Brass has a specific ductility that defines its ability to tension the bullet in the neck. If the bushing is too small it may cause difficulty seating the bullet but I'm struggling to see how it will provide significantly greater neck tension once expanded. Not poking at you, just trying to understand. Work hardened brass may be a bit different as it tends to have more spring-back but that would be realized in less neck tension, not more neck tension because you are down-sizing the brass.

Youre right theres nothing wrong with using smaler bushing.. altho this not creating those presure signs but theres things need to look when necking down brass more than .003 on loaded round. Not only that it lessen brass life by going to far in out overwork neck. . will it deform bullet by using too tight neck? I dunno.. have you load a bullet on a tight neck before and start seeking scraped copper from bullet? Is that a bad thing? As much as posible i like my bullet as perfect form as posible wheb geting release from the case. Now back to our brother problem i also got 260 im using 139scenar. Case capacity is litle more but even 43.4 start flatening my primer..im with those guy above saying litle too hot..
im here to learn..theres no bad advice for me its good when we share what we know..excuse my english its my second language..

 

[redbullitt]

Flat flat primers! I would definitely drop down to a lower charge weight. Sticky bolt is way past where i like to be for pressure.

If you have no better way of measuring the COAL that will put you into the lands with that bullet, take a sharpie and black a loaded cartridge (preferably no powder etc) at your COAL you want to try. Chamber it. If you are in the lands you will see definite marks on the bullet. It is always nice to know 100 percent. FWIW I have seen some variability, especially between lots of different bullets where ogive length can be notably different, so if you are right on the edge of pressure or seating depth it can make a noticeable jump in pressure.

Example: I have tons of pulled 175 smks. They MUST be sorted since ogive can vary as much as .060. If I loaded one at a very standard 2.80, dropped it in my 308 gas gun (max length is around 2.815) I would be way up into the lands and not even know it. Couple a normally nice 43.0g of varget to that and we get flat primers, blown primers, torn up brass, poor accuracy, FTFs, FTEs and all kinds of fun stuff. Not that I have ever had that happen… lol

You are using better bullets, but there can still be some variance between lots. I usually use Hornady amax bullets, any they can even vary a bit. If I were jamming them like the bergers like then it could be an issue. Maybe the lot you have is putting you a bit further into the lands, and if you are kissing them or jamming them a bit coupled with a hot load of powder I think it could be enough to show pressure signs where you normally would not have them.

You have a smaller bushing than I use. I go for around .003 tension usually, but I doubt yours would cause that much overpressure. I would not think it is optimal, but i cannot believe it would be more unsafe than the tension on most factory loads. .007 tension is not huge I don't think. You are just working the brass a little more and maybe making the seating a bit more difficult IMHO under NORMAL conditions where the scale is known to be correct etc. Again, if you are running more powder than you think though, it could be just enough to put you over pressure compared to a lower neck tension.

I am with flash hole on the brass! Make sure to check it with the feeler wire. Maybe you are pushing the shoulder back too much for that rifle.

If it ran okay last time and the temperature was even higher, something must have changed. Write down all the possibles, then work on them simplest first.

It is of course possible your scale was off. Maybe try some proof weights or something to verify? If your scale is indeed off, then it is hard to tell anything as you could be a grain or more overweight and not even realize. I would start there!

 

[JB02]

I've got a set, but not before i re-sized the brass i used. I'm going to take even more measurements and re-size some brass tonight.

This is the minor point. If you're able to close the bolt down with out any stiffness, you're headspaced just fine. Bumping the shoulder back only ~ 0.002" is just to minimize wear on your brass.

The big point is that you're loading way too hot; it's unsafe. Dial it down and look for the lower accuracy node.

 

[bornhunter04]

okay, yes those charges were way too hot, that was never the question. the question was why would the "same" charges that shot fine on saturday show extreme pressure signs on Wed.?

so the headspace was way off. but is now set correctly for a .002 bump. also, when i got home i took alcohol and cleaned the contact points on my 505 scale and re-weighed my control charge. it did in fact weigh out at 43.9 gr so this charge was .3 over the higher charge which i assume means the "43.2gr" charge was actually 43.5gr and with the combined excessive headspace reduced case capacity thus resulting in the pressure signs. I believe 43.6gr of h4350 at a properly sized cartridge at 2.80coal is a safe load in my rifle. of course it goes without saying that i will work back up to it just to be absolutely certain.

 

[JB02]

okay, yes those charges were way too hot, that was never the question. the question was why would the "same" charges that shot fine on saturday show extreme pressure signs on Wed.?

so the headspace was way off. but is now set correctly for a .002 bump. also, when i got home i took alcohol and cleaned the contact points on my 505 scale and re-weighed my control charge. it did in fact weigh out at 43.9 gr so this charge was .3 over the higher charge which i assume means the "43.2gr" charge was actually 43.5gr and with the combined excessive headspace reduced case capacity thus resulting in the pressure signs. I believe 43.6gr of h4350 at a properly sized cartridge at 2.80coal is a safe load in my rifle. of course it goes without saying that i will work back up to it just to be absolutely certain.

I think you're playing with fire here and missing the point. Those charges you loaded on Wednesday were probably right on the knife's edge. Is there some performance mark you're trying to meet? Run the ballistics for the two loads to convince yourself the juice isn't worth the squeeze; what will you gain, .1-.2 mils elevation/wind downrange? Loading your CM with 43gr+ H4350 is going to be hard on your barrel and brass even if it's just on the knife's edge on not showing any pressure signs. You're better looking for a node about 1.6gr below your hot rot load you fancy now. Your rifle, your brass, and your ass will thank you for it.

 

[Macmathews]

I'm a little late to the party..
But all these loads look way over book max ??


Kyle

 

[flashhole]

If you're able to close the bolt down with out any stiffness, you're headspaced just fine.

I will caution you this is not a true statement. You can chamber a 308 in a 30-06 and close the bolt just fine. Extreme example yes but he had a headspace issue that he has corrected. There is a lot more to proper case sizing than just being able to close the bolt.

 

[bjay]

I will caution you this is not a true statement. You can chamber a 308 in a 30-06 and close the bolt just fine. Extreme example yes but he had a headspace issue that he has corrected. There is a lot more to proper case sizing than just being able to close the bolt.

Pls educate me.. about your statement..ive always been doin it this way once bolt close smoth..measure it wuth comparator shoulder got bump about 0015 -0020 i caled it done!

 

[flashhole]

What you described is correct. The way the statement was presented it could be very misleading to new reloaders. Suppose you shaved 1/10" off the bottom of your FL sizing die and sized your case. Or worse, you bought a die set where someone had done that and you didn't know it was modified. Sizing the case with the short die will allow it to fit in the chamber and it will likely go boom when you pull the trigger but you create an unsafe situation with excessive headspace. All I'm saying is you need to know what you're doing, check your results and not take things for granted. Checking with a comparator is not called for in your die instructions but it is a sanity check ensuring all is well. I don't own a set of dies that will size the case .025" shorter than SAMMI specs but if that is what the OP has he needs to be aware of what constitutes proper use of his specific die set. Just because it chambers does not make it right.

 

[JB02]

I will caution you this is not a true statement. You can chamber a 308 in a 30-06 and close the bolt just fine. Extreme example yes but he had a headspace issue that he has corrected. There is a lot more to proper case sizing than just being able to close the bolt.

There was context to my discussion, which I'm pretty sure everyone understood. I understand your point; however, I wasn't referring to every extreme instance in a broad sense, but narrowly to sizing cases previously fired in his rifle. And, in any event, his brass sizing technique is IMO just a minor nuance of this thread and his real issue is that he's trying to excessively hot rod his ammo.

 

[bornhunter04]

Worked up my loads this morning and went out and shot them.

No flattened primers this time. So I feel pretty confident that my head-space and my scale being off were my issues with the last batch. Also, I mirrored the seating depth of the 42.4gr load.

In the pictures of the primers going from left to right, colored primers are 42.4gr then 43.0, 43.2, 43.4gr of H4350.

At 43.4gr the bolt felt like it required just a shade more force to open, not what i would consider sticky bolt but you could tell it was definitely a hotter charge. I think, 43.6gr is still safe in MY RIFLE, but I'm happy with the velocity and accuracy I'm getting with 43.2gr so I'm going to stick with it. Thanks for the help in getting this figured out.

 

[bornhunter04]

I've got one more question about this. What should i do with the brass that was resized to much but not fired (i.e. pulled rounds or brass that was sized and prepped but never loaded or fired). The ones that show far to much pressure, i'm just going to keep as a good reminder, but not load with them again. Are they save to shoot with a minor charge? Or do i need to re-form them, or should i just pitch them. We're only talking about a 20 or so cases. So not a ton, but if there is still someway to use them I'd like to.

 

[limige]

You've got something going on.
I've ran 43.5 gr of h4350 behind a 140 vld with no pressure signs.

Let us know when you pin it down

 

[bornhunter04]

You've got something going on.
I've ran 43.5 gr of h4350 behind a 140 vld with no pressure signs.

Let us know when you pin it down

Already did. It was a combination of sizing the brass too much and my scale being off .3gr and the seating depth being off. I successfully ran 43.4gr of H4350 behind the 130 vld's without any pressure signs. 43.2gr gives me good accuracy with close to the velocity i was looking for.

 

[limige]

Gotcha lots of reading thought you were still on it.

What primers are you running?

I have yet to see one of my cci's do that. .

 

[BC 6.8]

I have a Savage 6.5 Creedmoor, and my load for the 130 Berger is 43.8 gr H4350, Fed 210 primer seated to 2.850" which is about 0.040" jump for me. I have loaded up to 44.1 gr H4350 without pressure signs. All of my loads so far have been with new brass. That being said, different lots of powder will have different results, so always go off of what your rifle is telling you. I would say that your loads that looked to have been over pressure are likely the result of bumping the shoulder back too far. There is a very good example of this over in the 6.5 Creedmoor loads thread where Skigolfmike over-sized some of his cases.

Most people are using a .287 or .288 bushing and have a loaded round neck diameter of around .290, so I think you are using the right bushing.