Home Forums Reloading Reloading Software H4831 vs. H4831sc?

I have a great shooting .270 Win. which I developed a load for using 60 gr. of H4831sc pushing a 130 gr. Barnes.

I loaded some duplicate loads last winter using H4831, and took them to the range. Two of the first three shots blew the primers (and printed 4 MOA instead of sub MOA) something that has almost never happened to me over the years loading thousands of HP rifle loads.

I took the rest of the box home and pulled them down. Maybe some variance of charges +/- one grain. Everything else in order (brass trimmed, proper OAL, hadn't misloaded 140 gr. pills, etc.). Can batches of powder vary enough to blow primers? Is there typically a pressure difference between standard 4831 and short-cut?

How to put this nicely??? Did you not start low and work up? Why does this always have to be stressed and suggested?

I get your point. But I also infer that you don't know the answers to my question "Is there typically a pressure difference between standard 4831 and short-cut?"

I stacked these what turned out to be over-pressure loads the middle of MT winter, meaning I didn't take the luxury of driving 10 miles out an ice-covered mountain road a couple times to spend time at a -10F bench to "work up." I just trusted the manuals and what I'd already experienced with this rifle and chamber, and that I was under Jack O'Connor's favorite .270 load of 62gr. of H4831 pushing a 130gr. pill (per Waters).

Do you actually have experience with these powders and this load?

Regards,
GC

Bud Waters and O'Connor weren’t shooting Barnes, sorry big difference.
As far as H4831/4831SC you show me a loading manual that makes a distinction between the 2, so your answer is no, IMR4831 yes or used to be.
Now ~1 grain when listed is 60C @ Hodgdon for that bullet a+1 grain @-10 maybe safe. +1 grain @80+ I wouldn’t even attempt.
Sorry

Here are some things to check:

What did the chronograph read for velocity on those two shots where the primers blew?
How old are those cases - how many times have they been reloaded?

I've not seen much of a difference between old 'crunchy' H4831 and newer 'short cut' H4831SC. Hodgon claims that H4831SC is a 'exact ballistic copy' of H4831: https://shop.hodgdon.com/hodgdon-h4831sc/

Plus, for that powder and bullet combo, Hodgdon shows 60 grains as a max charge: https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=54

Were the loads that blew the primers being shot in the same rifle that was the 'test mule' for developing that load? Or were these loads developed in another 270 and then reloaded and shot in a different 270?

According to Hodgdon NO diff.

Throw you curve ball, have seen that compressed loads or heavily compressed as in 110-115 % have a tendency to push the bullet out over time.

I am working with jugs of each and see no difference in either my 30-06, .270, or 6.5-06. I have only used SC in my new to me .284.

Now that is interesting and a possible explanation.

I wasn't shooting through a chrony, so no info. there. Loads being shot in same rifle. Brass was 2-3X fired. I did rebuild the loads again two days ago (same brass, working up), and got to 60gr. of H4831sc with no pressure signs on a warm day. I did shorten the OAL to 3.23 to make sure I wasn't up against the lands. 4-shot groups, 3 touching.

I have reached pressure sooner than expected with some Barnes bullets which for me have generally done best with some jump or shorter COAL than other bullets.

GrouseChaser,

You don't mention which 130-grain Barnes you tried.

As more than one pressure-lab technician has said to me, in various ways, "a chronograph is a handloader's best friend."

My current batches of H4831SC and "long cut" H4831 get within 25 fps of each other, when used in the same charges, with the same bullets, seated to the same depths. But that doesn't mean other manufacturing lots won't vary more.

You might check the case length on those 2-3 times fired cases.

John

These were TTSX pills (which should be lowest pressure Barnes with the grooves, correct?). I keep my brass trimmed and all measured within spec. Good point on the chrony... I have one I should use more. But honestly, I tend to seek accuracy more than velocity within 5gr. of published max load. Thanks for the input.

Why would we ever look at Barnes loading data ?
The loads for all three 130 gr are the SAME.
Max with 4831 is 57 gr.
HINT: A sierra cup and core like JOC used is not the same as a monometal like the TSX.

Well since this is the reloading software section

This is using his seating depth of 3.230 and varying the case capacity

68 grains



69



70



71




I didn’t go lower than 68 as it wouldn’t serve an obvious purpose but in my opinion 60 is on the very jagged edge depending on actual case capacity of the brass used.
OP use your chronograph it just might save your rifle and appendages.

I don't know your source for the Barnes data at 57 gr that you quote but the current load data on Barnes's web site shows a max charge of 60.5 grains of H4831sc for their 127-130 grain bullets:
https://www.barnesbullets.com/wp-content/uploads/2023/01/270WinchesterForWeb.pdf

The Hodgdon H4831 data that I cited earlier was for a 130 gr Barnes TSX bullet in Win cases with WLR primers. Hodgdon lists a max charge of 60 grains of H4831 for a Barnes 130gr TSX bullet.
Here's the Hodgdon link again but remember you have to select the cartridge, bullet weight, powder, etc: https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=54

Both of those sources indicate that GCs load should be acceptable given good cases and appropriate bullet seating depths.

Here's another thought. Did the primers actually blow (pop) out of their pocket in the cases, or was there just some leakage of gases around the perimeter of the primer pocket? If it was just leaking gases it may have been due to a batch of defective primers. What brand were the primers?

A few (several?) years ago, Winchester produced several lots of primers where the metal cups were defective. IIRC, the primer cup metal was too thin and/or not properly annealed, and upon firing the curved edge of the primer cup metal failed and high pressure gas leaked out. Many folks had those defective primers, myself included, and Win finally replaced those defective primers. The sad fact was the high pressure gas leaks from those defective primer cups ended up damaging lots of bolt faces.

Hard to believe that anyone would take the opinion of a powder company over that of the bullet maker.

Gee, wonder who tested more loads (if any) with the Barnes bullets and 4831 ?

Especially when NONE of you haver a pressure transducer on the OP s rifle.

My load blows out/punctured primers but I'll blame it one the power.

Believe it or not, not all load data is pressure tested. Some is, some is derived from Quickload.

LOL, who at Barnes told you that ?
Ever visited them ?

The inconvenient truth.
https://bulletin.accurateshooter.com/2011/04/evaluating-pressure-signs-in-reloaded-cartridge-brass/