Is a chronograph about the only tool one can use to gauge pressure, comparing it to velocity tables?

I have loaded my 270 to flatten the primers but have never been able to get a sticky bolt or poor case extraction. I run out of case to be able to put any more powder in.

Also, is it normal to get a flattened primer on the first and second shots but after the chamber has heated up and expanded, get no more flattened primers?

quote:

Originally posted by ar corey:
Is a chronograph about the only tool one can use to gauge pressure, comparing it to velocity tables?

THE CHRONY IS NOT A PRESSURE GAUGE and never think of it as such. It's a velocity gauge and that alone!

quote:

I have loaded my 270 to flatten the primers but have never been able to get a sticky bolt or poor case extraction. I run out of case to be able to put any more powder in.

When I loaded the .270 with 100 grain bullets and IMR-4831 (or was it H-4831?) I never could get all the powder in the case. I got to the point that I filled the case and brushed off the top and stuffed a bullet in.

Today (if you choose) you can make a brass rod for your seating die and fill the case half way and compress the powder and then fill the case again and again compress the powder and then again fill the case and finally stuff in a bullet.....but you better be weighing all the powder because you definitely can stick the bolt doing this!!!!!

I'd opt for using a slightly faster powder like
H-414 or RL-19 or H-4350. as all that compression (while it works) just isn't worth it in my estimation.

quote:

Also, is it normal to get a flattened primer on the first and second shots but after the chamber has heated up and expanded, get no more flattened primers?

No it is not.....the miniscule expansion due to an amount of heat will not cover for excess pressure.

Something else is going on here.

As vapdog said. You can not use a chrono as a pressuregaugething.
Flat primers can happen due to soft primers, too hot load or maybe your cases have been molested several times with to heavy loads so your primers is maybe not sitting tight enough.
Maybe you are resizing your cases too hard?

I don't know but you better give us your load data.
1. What kind of cases.
2. Times reloaded
3. Primer type
4. Powder used and amount
5. Bullet type
6. Kind of gun
7. COL

1. Remington cases.
2. 3-5 x's reloaded.
3. WLR primers.
4. H4831, 61.5 gr's.
5. Barnes TSX 130's.
6. Browning A-bolt Medallion.
7. Don't know COL, no caliper owned.

I guess what I should have asked is what does everybodies primers look like after firing an average, high power load?

1. Do they look the same before firing?
2. Are they slightly flattened but still showing the open groove around the primer?
3. Are they completely flat, spread out and flush with the case, showing a tiny hair line groove around the primer.
4. If number 3, is this dangerous with no bolt stick?

Like I said, I should probably get a chrono. While it is not a pressure gauge, if I am ripping 130 grain bullet's at 3250 fps with a .270, it is probably developing unsafe pressures despite lack of the bolt sticking.

Hodgdon lists the Barnes TSX 130 grain bullet for the 270 Win (I assume it’s a Winchester).

On their website they say that 60 grains of H4831 is Maximum and that it’s a compressed load and generates 59,000 psi of pressure.

You are stuffing 1.5 grains more in that already over loaded case.

Just for grins I plugged your information into Quickload. It said that your fill ratio is 115.1%, P-max for the 270 Win is 65,000 psi and that your load exceeds that by 1,149 psi.

This load may or may not be dangerous in your gun. But one thing is for sure, your load is at the very top end for H4831.

Hi!

Okidoki
Looks like you have not directly checked any reloadning data previously for your more than hot load.

I found some data too and even that book suggest you to back off at least 1,5 grains and even then it might be too mutch for your gun.

You better start over again. Pull out all bullets of remaining lot.
If primers will seat too easy - scrap those cases.
Follow safe data instead.
Anyway smart to come in here anyway. I did learn most of my reloading skills on web.
Please continue with reloading, but do not start at max in the future. And buy a caliper. Not having a caliper is a big sin. Even the cheapest one is better than non.
Tell me how where you supposed to know if a case is too long after several reloads?
Basic tool!!!!! get it......

full sized or new brass can/will show a flatter primer "spread out" filling the chamfer around the primer pocket more than a fireformed, chamber fit, neck sized only reloaded brass that has tight head space fit

Id say 61.5 gr H4831 is very hot load especialy with Remington brass.

Try about 55 grs in a neck sized fireformed case and look at the primer, then work up and examine the primers as powder charge increases

Some 40+ years ago, concave primers were common fare so "flattened" primers actually meant something. Today's primers actually start out flat so it's perhaps the least reliable sign of pressure available to us.

Today, in my opinion, overly flattened primers is more often a sign of excessive headspace, either due to an overly long chamber, which is unusual, or, much more common, excessively resized brass.

Anyone attempting to get pressure guidance from a chronograph is courting disaster, especially if using a powder that is "fast" for the cartridge.

quote:

Originally posted by David Walther:
Hi!

Looks like you have not directly checked any reloadning data previously for your more than hot load.

The Lyman reloading manual gave me a good idea, basically 58 grains was max for H4831. I was curious how much I could load though. I just kept going 1/2 grain at a time untill I got to 61.5. Never once had any signs of a sticky bolt.

quote:

I found some data too and even that book suggest you to back off at least 1,5 grains and even then it might be too mutch for your gun.

I never got into shooting any groups with that load to see if it was even accurate, it may have been very inaccurate.

quote:

You better start over again. Pull out all bullets of remaining lot.

I don't have left but probably won't max out like that again.

quote:

Follow safe data instead.

I guess just curious what my gun could take. I would load up 1/2 grain more, then place the gun on my archery bag with the stock against an old tire of a junk vehicle. I then tied a string to the trigger and went back behind the vehicle and pulled the string. Bang!

quote:

And buy a caliper. Even the cheapest one is better than none. Tell me how where you supposed to know if a case is too long after several reloads?
Basic tool!!!!! get it......

What I do for this is take a new case and set my Lyman trimming lathe to this length. Then I lock the trimmer. After each shot, I resize the case then trim it to the stop. I then place the case beside the new one and make sure it is exactly the same length in case a mistake was made. Not the most precise way of keeping data etc. but those calipers can run $75-$80. Still, you are probably correct, I should get one.

quote:

Originally posted by GSP7:
Try about 55 grs in a neck sized fireformed case and look at the primer, then work up and examine the primers as powder charge increases

Makes sense.

How does one neck size in a 2 die set without buying a neck die?

How do you punch out the fired primer?

quote:

Originally posted by ar corey:

quote:

Originally posted by GSP7:
Try about 55 grs in a neck sized fireformed case and look at the primer, then work up and examine the primers as powder charge increases

Makes sense.

How does one neck size in a 2 die set without buying a neck die?

How do you punch out the fired primer?

I RCBS dies you can adjust the primer extraction pin. If you back up your die a couple of turns you will only resize the neck of your cases. So adjust it so you clearly see that almost the hole neck have been resized. For a test turn it up way to mutch and then adjust till you get it right. When it is right then adjust the primerextractor.

By the way, when adding a 0,5 grain at the time to see when you are close too disaster you really play with fire. Loading data in the books are pressure tested with professional tools. They know what is max. If you really need more - go bigger...

A caliper is even here in norway possible to get for $10-15.. I know RCBS calipers cost about $80 but it is not worth it.
Go bye a caliper at a normal tool store, they have the cheap ones.

/

quote:

The worlds largest regulating body on firearms pressure says you can and they do !

But what you can not measure with a chrone is friction and how thight a barrel is, and those 2 factores is so significant that a chrono is close to stupid to use as a pressure gauge.

But if you have some experience with factory ammo and its velocity in different guns you can by time learn maybe how your gun is. In such a matter a chrono will be a helpfull guide and to a sertain degree sufficient.

In this tread it is obvious that this is not the case.

And alf is WRONG AGAIN!!! As usual.

Hard to believe a person who knows so little about Internal/External Ballistics and Game Anatomy continues to post nothing but ignorance, rather than learning from people who actually understand. Pitiful!

/

Here we go again

I hear the trumpets it blow again . . .

Alf summed up best current practice. Hotcore will rant about all the old guys used his system. In the end, you'll have to figure out whether you can take your calipers and measure cases to determine if your data makes any sense. Current thinking is that Hotcore's methods are not considered accurate. He will insist it is.

As you approach the maximum velocity posted in a reloading manual, carefully working up your load, you will find that your rifle is "loose", or "tight" or "average," ie, you will get a little more, a little less or pretty much right on the book velocity. It is never a good idea to exceed the max posted load regardless of velocity. It can be done and I do it but only in special circumstances (generally with old cartridges in modern rifles where standard pressure is kept low out of respect for old rifles. You have to know what the standard is and it helps to have a modern equivalent to compare it to.)

I believe that for those of us without ballistic labs, the most useable measure of pressure is how long one's brass last. If you get five loads with a magnum without loose pockets or eight in a standard loading, you've got a keeper.

Now Alf and Hotcore, I want a clean break and no hitting below the belt. Go to your respective corners and come out fighting. Kudude

quote:

Originally posted by kudude:
...Alf summed up best current practice.

quote:

I believe that for those of us without ballistic labs, the most useable measure of pressure is how long one's brass last. If you get five loads with a magnum without loose pockets or eight in a standard loading, you've got a keeper. ...

Hey Kudude, How many trips to the Range does it take (for the Rookies) if they choose to follow that advice?

By the way, I agree what Kudude mentioned is a good way to know you are not exceeding SAFE MAX Pressures.

I wish Alf and Hot Core were a little less tiresome.

You can get flattened primers from too much headspace too without any pressure signs.

quote:

It is never a good idea to exceed the max posted load regardless of velocity

and there is little point in doing so.

My question is .... if a max load is given at 2,900 fps say for a 180 gr bullet in a 300 Win Mag, what will one achieve to push the envelope another 50 fps (1.7%) or 100 fps (3.4%)? These increments in velocity are marginal and insignificant in my opinion.

Warrior