.270 win help. Cratering primers update Page 8 post 78
- Thread starter bobjoe
- Start date
To answer more questions. Yes the brass has been trimmed to length. It is the newer powder that has the plastic screw on lid. Not an older can of powder. I know the load is hot, I’ve already reduced the load. My question is why, when it is so far under published max loads, is the load showing over pressure? That is what is confusing me.
3.3 oal might be jamming the lands, causing the spike.
Over zealous cleaning of the primer pocket, making it larger.
Then the trim length in comparison to the chamber. Take a freshly prepped case and rack it through the gun and inspect with a magnifier to see if the chamber put some crimp on it. Measure before and after.
Over zealous cleaning of the primer pocket, making it larger.
Then the trim length in comparison to the chamber. Take a freshly prepped case and rack it through the gun and inspect with a magnifier to see if the chamber put some crimp on it. Measure before and after.
Falconflyer
CGN Ultra frequent flyer
Many years ago I had a 270 win that produced dangerously high pressures with loads of 4831 and 4350 barely above published starting data. Long story kept short, I never figured out why it was doing that but on a whim I decided to try 7828 and found that I was able to go up to the book max loads with no signs of excessive pressure at all. I’m out of the country right now or I would look at the load data I saved from that rifle and give more details on what I was doing.
I have an unusual problem that is perplexing me. I have been reloading for years. I am trying to find a load that would work for two different .270 win bolt actions that I have. I planned on using a 130 gr barnes ttsx. Doing proper development I started at 54gr with max being 58 using IMR 4831 according to the barns book. I also had 215mag GMM primers. I went out and shot and found that 55gr was the most accurate load for both but I had some concern as the primers were cratering/flattening/backing out and I had some marks on the head of the brass. Crony was showing 3150 fps. Which is fast for 55gr but within the range of the barns book. Seating was at 3.300 originally.
Wanting to be safe I back the load off down as low as 52gr and seated the bullet into 3.230 I tired CCI 250 primers and even tried a Speer 130gr BT that I had on hand. No matter the type of brass, primer ect that I use the primers crater and are starting to flow out of the brass leaving a ring on the bottom of the primer. 52gr is well below the starting load. I’m at a loss. Bolt hasn’t been hard to open at all. Brass measure proper after firing in all aspects except the primer pockets. They start at .205 and after firing some of them are .207 up to .214 for one and it had gas escape from it on firing.
Is this a head space issue? Rifle is a savage 111.
Some pictures to show what is happening
I suspect over sizing of the brass, shoulder set back too far, try neck sizing your brass and see if that clears it up.
Hmmm....sounds odd, and way over pressure as we all recognize.
The question has been asked already about excessive headspace, but you have not confirmed that yet in a response. Can you confirm a comprator measurment for the difference in HS between your fired cases and what you size them at? Just a confirmation check to make absolutely sure your die is set right.
A check on your balance or scale to see if it zero's (if not done already) should be done. Just getting all the potential variable out of the way.
I do not have a Barnes manual, but Barnes publishes select online load data, and its different from what you are citing from your Barnes manual.
https://www.barnesbullets.com/wp-content/uploads/2023/01/270WinchesterForWeb.pdf
For the 130gr TTSX and IMR 4831 (they used Rem 9 1/2 primer), currently Barnes' website is showing min 51.3gr, and max 57.0grC, with the max velocity at 3167 fps.
The 52.0 gr load you tested is not below min charge, according to the latest online load data. Maybe Barnes made some data changes from their previous manual?
Your velocity was essentially at max, given chrono accuracy and environmental conditions. If you want to stay with the magnum primer, I think you need to reduce powder charge way down to bring that velocity and pressure down. The Barnes online load data shows the min charge 51.3gr velocity at 2861 fps. That is a big difference from max velocity. (2861 fps I would think should be fine for bullet terminal performance at normal hunting distances).
That mag primer could be adding perhaps adding 50 to 100 fps velocity (or maybe more), which could be measured in a primer test comparison on your chrono. Velocity is not pressure, but its a rough surrogate, meaning your rifle does not like that max velocity and it needs to be significantly reduced (if all the other variables check out OK).
The question has been asked already about excessive headspace, but you have not confirmed that yet in a response. Can you confirm a comprator measurment for the difference in HS between your fired cases and what you size them at? Just a confirmation check to make absolutely sure your die is set right.
A check on your balance or scale to see if it zero's (if not done already) should be done. Just getting all the potential variable out of the way.
I do not have a Barnes manual, but Barnes publishes select online load data, and its different from what you are citing from your Barnes manual.
https://www.barnesbullets.com/wp-content/uploads/2023/01/270WinchesterForWeb.pdf
For the 130gr TTSX and IMR 4831 (they used Rem 9 1/2 primer), currently Barnes' website is showing min 51.3gr, and max 57.0grC, with the max velocity at 3167 fps.
The 52.0 gr load you tested is not below min charge, according to the latest online load data. Maybe Barnes made some data changes from their previous manual?
Your velocity was essentially at max, given chrono accuracy and environmental conditions. If you want to stay with the magnum primer, I think you need to reduce powder charge way down to bring that velocity and pressure down. The Barnes online load data shows the min charge 51.3gr velocity at 2861 fps. That is a big difference from max velocity. (2861 fps I would think should be fine for bullet terminal performance at normal hunting distances).
That mag primer could be adding perhaps adding 50 to 100 fps velocity (or maybe more), which could be measured in a primer test comparison on your chrono. Velocity is not pressure, but its a rough surrogate, meaning your rifle does not like that max velocity and it needs to be significantly reduced (if all the other variables check out OK).
- Location
- Van. Is. B.C.
I would start checking the basics, you say your brass is trimmed correctly that’s 1.
How much jump for the bullet and are you tight to the rifling 2.
Have you tested your powder scale with check weights 3.
Oversize would cause flattened primers but brass flow into ejector, I don’t know about that too 4.
Not to insult you, but how clean is your barrel, a friend had a 308 Norma that showed excessive pressure and no rifling, hours of scrubbing and everything was back to normal 5.
You don’t happen to have a 7mm and any .284” bullets lying around do you that’s only a .007” increase 6.
How much jump for the bullet and are you tight to the rifling 2.
Have you tested your powder scale with check weights 3.
Oversize would cause flattened primers but brass flow into ejector, I don’t know about that too 4.
Not to insult you, but how clean is your barrel, a friend had a 308 Norma that showed excessive pressure and no rifling, hours of scrubbing and everything was back to normal 5.
You don’t happen to have a 7mm and any .284” bullets lying around do you that’s only a .007” increase 6.
To be clear have you used these rifles before and are known to be "normal" as well have you used this can of IMR4831 before and know it is "normal".
Everything you are doing sounds ok to me but I have never in all my over 40 years of reloading seen pressure sign like your pictures clearly show and I load hunting ammo HOT.
My go to 270 load is 59 grains of IMR4831, CCI 250's a Sierra 130 BT and Federal brass...Chronographs at 3150.
Everything you are doing sounds ok to me but I have never in all my over 40 years of reloading seen pressure sign like your pictures clearly show and I load hunting ammo HOT.
My go to 270 load is 59 grains of IMR4831, CCI 250's a Sierra 130 BT and Federal brass...Chronographs at 3150.
So to clarify a couple things. I took the rifle to a smith. Chamber is ok. Headspace is perfect. Bolt is perfect. Nothing unusual for the rifle. So my issue is the reloads.
To check the lands, I was doing it an old way. Cut 80% of the way through a neck of a case after sizing. Mark bullet with sharpie. Put in and close bolt. Remove and measure. Set seating die to oal for first. Make a second round at bolt closed oal. If the bullet is set deeper I know as I take a before and after measurement. If the bullet pulls out I will see it as the sharpie marks are there after sizing and will show if it is pulled out.
Once I’ve done this I then check to see if it fits in the mag. If it does not I seat it until it fits in the mag. Doing this I had an oal of around 3.330, that was from the top of the bullet. That was 0.050 off of the rifling. After seeing the pressure I reduced the load and seated the bullet in deeper. Where it was .180 off the rifling. Trying that with two different bullets gave the same result. I then tried different brass brands. Different primer brands. Mag vs standard all produced the same result.
I know my method is not perfect but I have not had a problem like this before and done this same process with multiple different rifles in different calibers.
The powder was brand new. I have not used it in any other rifle or load. It was bought from a store not private sale. Primers are all kept dry ect. I have tried federal, Winchester and Remington brass. Federal was just the first ones I tried and no point of multiple pictures of the same thing. It’s the brass I have so trying to work with it.
I bought a modified case kit to double check my measurement properly to see if something is off with my seating depths.
To check the lands, I was doing it an old way. Cut 80% of the way through a neck of a case after sizing. Mark bullet with sharpie. Put in and close bolt. Remove and measure. Set seating die to oal for first. Make a second round at bolt closed oal. If the bullet is set deeper I know as I take a before and after measurement. If the bullet pulls out I will see it as the sharpie marks are there after sizing and will show if it is pulled out.
Once I’ve done this I then check to see if it fits in the mag. If it does not I seat it until it fits in the mag. Doing this I had an oal of around 3.330, that was from the top of the bullet. That was 0.050 off of the rifling. After seeing the pressure I reduced the load and seated the bullet in deeper. Where it was .180 off the rifling. Trying that with two different bullets gave the same result. I then tried different brass brands. Different primer brands. Mag vs standard all produced the same result.
I know my method is not perfect but I have not had a problem like this before and done this same process with multiple different rifles in different calibers.
The powder was brand new. I have not used it in any other rifle or load. It was bought from a store not private sale. Primers are all kept dry ect. I have tried federal, Winchester and Remington brass. Federal was just the first ones I tried and no point of multiple pictures of the same thing. It’s the brass I have so trying to work with it.
I bought a modified case kit to double check my measurement properly to see if something is off with my seating depths.
pete dobinson
CGN frequent flyer
- Location
- Courtenay BC.
Check your powder scale.
Further update. With the modified case gauge, to the lands measuring off of the ogive 2.839. my original loaded round was 2.805 making it .034 from the lands. With my load reduction and seating the bullet in deeper I found that it was as low as 2.705 being .134 off of the lands and down to 52gr of powder still getting pressure signs. Comparing a resized case vs fired vs virgin vs modified they are all within .001-002 of each other with the virgin brass having the shoulder back the furthest.
So gun is ok, brass is ok, scale is ok, seating depth is ok. Powder charge is under max load. Primers are ok. My conclusion at this point is it has to be the powder type. It just doesn’t like it. Is there anything else I can check????
So gun is ok, brass is ok, scale is ok, seating depth is ok. Powder charge is under max load. Primers are ok. My conclusion at this point is it has to be the powder type. It just doesn’t like it. Is there anything else I can check????
Just because that load is less than what the book says is MAX!, is your barrel & all components the exact same as they ran their pressure tests in/with?
If not, then the pressure of that load in your rifle using your components was/is TOO HOT.
Quicker twist, smaller bore/groove dimensions, less capacity of your brass, the list goes on and on and on as to why your pressures are hotter than what the "book" says they should be.
If not, then the pressure of that load in your rifle using your components was/is TOO HOT.
Quicker twist, smaller bore/groove dimensions, less capacity of your brass, the list goes on and on and on as to why your pressures are hotter than what the "book" says they should be.
So I ran some numbers in QL:
.270 Winchester, 22" bbl. (Savage 111), 130 gr. Barnes TTSX, C.O.A.L. 3.300" 55.0 gr. IMR4831
Case capacity 63.5 grs. 3,147 fps @ 71,912 psi
Darned close to your results; NOTE the pressure!
While I've never played with a .270, for the purposes of this discussion, a .30-06 is not terribly different. In my collection of .30-06 brass, I've got 8 different brands, although not Federal. Case capacity runs from 62.5 grs. to 72.3 grs. (the 9.8 grs. represents a 16% difference)
Now let's run the same numbers for the largest capacity case; in my .30-06 brass, it holds 72.3 grs.:
2,927 fps @ 52,504 psi
Using Barnes Max of 57.0 grs., it's still only 3,129 fps @ 58,645 psi in your 22" barrel, compared to Barnes' test barrel of 24" [only velocity changes with a shorter or longer barrel, NOT pressure, as long as the barrel is the same one.
.270 Winchester, 22" bbl. (Savage 111), 130 gr. Barnes TTSX, C.O.A.L. 3.300" 55.0 gr. IMR4831
Case capacity 63.5 grs. 3,147 fps @ 71,912 psi
Darned close to your results; NOTE the pressure!
While I've never played with a .270, for the purposes of this discussion, a .30-06 is not terribly different. In my collection of .30-06 brass, I've got 8 different brands, although not Federal. Case capacity runs from 62.5 grs. to 72.3 grs. (the 9.8 grs. represents a 16% difference)
Now let's run the same numbers for the largest capacity case; in my .30-06 brass, it holds 72.3 grs.:
2,927 fps @ 52,504 psi
Using Barnes Max of 57.0 grs., it's still only 3,129 fps @ 58,645 psi in your 22" barrel, compared to Barnes' test barrel of 24" [only velocity changes with a shorter or longer barrel, NOT pressure, as long as the barrel is the same one.
