Jam in 30BR (and similar)

S

SGJennings

New member
OK, I'm snowed in and need mental distraction...

Seems like almost everyone shoots a lot of jam in the 30BR (and the like....hereafter just saying 30BR)

What is the intended outcome of a lot of jam in the 30BR?

Does yours just not shoot without a lot of jam, or does the jam buy consistency?
 
seating depth

I agree too many factors affect this, I start just kissing an if that doesn't work move in and out till I get what I want. Keep in mind that some bullets ( I don't think most use them for 100 to 300 benchrest) require a considerable jump.
 
I was hoping to discuss tension in a parallel thread. It's going to snow through tomorrow. I'm going to need a LOT of distraction.

So how many folks are shooting jam and how many are just on the lands?

I've got a load that has shot some outstanding groups. It's just touching the lands, only 1 thou tension and a, relatively, mild powder charge. Not a fat bullet, either. 308 shank, 3083 pressure ring.

I'm not feeling comfortable with this and am exploring other combos. Starting at the other end of the seating range, 3 thou tension and the next two higher "nodes".

Someone talk here, or I'm gonna have to go shovel snow again!
 
Jam

I shoot mine just touching with the BIB 112 7 ogive. I shoot a moderate neck tension, a .325 bushing with a .330 neck, set up with .002 clearance. With springback, it reall amounts to about .002........jackie
 
From just touching, I'm into the lands about .008". I just want to "feel" the bullet as I close the bolt. I use a bit more neck tension than most I imagine, a .323" or .324" bushing with a .3275" or .328" loaded round. I anneal regularly to keep neck tension consistent, although I've been thinking about making some new cases as I'm stuck in the same situation as you are. It's been a LONG time since I made any 30BR cases...
 
Let the Barrel Talk

I have shot just kissing lands, at about .008 beyond the kiss, and as much as .020 into the lands. After I find my node using the heaviest jam I can get, I try other setting for the best jam with that charge of powder. That is where I stay with that barrel/bullet/powder combo until I start getting inconsistency. I prefer to have the jam be the minimum possible so that I can eject a loaded round without dumping the powder charge, but only if it is working properly. Most of my testing has revealed that .008-.010 jam shoots as well as the heaviest jam the combo will take. I have yet to find a combo that likes much jump but I haven't tried many brands of bullets. I have been very happy with the two that I have used. Randy J.
 
I was glad to see this thread since I just finished loading for my just finished new 30BR and I had pretty much the same ideas as Mr. Schmidt on neck tension.

Not to try to hijack the thread, but how does everyone feel about H4198 and how heavy a load for 50 to 70 degree weather? The load info I have seen seems like folks are loading a lot hotter than my quickload program thinks I should even with with long seating.
 
Here is a page with some load data: http://www.6mmbr.com/30BR.html .

I'm shooting a 30 Major which is a 6.5 Grendel necked up to 30. I've only tried N120. I see no reason to try to reinvent the wheel there.

I've got a load that has shot some good 3-shot groups in the one time I've been able to shoot (danged snow storms!). I'm a bit worried about the consistency over the long term, hence this thread.
 
Danger!!!!!

SGJennings....
Please don't load 33.5 to 35 grains of N120 in that case I wouldn't want to be anywhere around if you that happens!:eek:
 
I have been using

heavy tension for a couple of years with my 30's I find where my bullets just kiss the lands then load groups of 3 rounds seated EXACTLY .003 in until I find a round hole. I most often find it at either .006 or .009 in. I do have one barrel that likes to kiss the lands.

All that said and some may have read my post about using my tuner to tune a load of unknown quality. I used a stout load of a powder not many people use and 115 Berger bullets seated .006 in. I just kept turning the tuner a little at a time until I had a TINY round hole. I shot a second group to make sure the hole stayed small.

I am gonna try that load again Sunday. We'll see if it stays in tune.

In my opinion, maintaining consistent OAL's measured at where the bullets touch the lands is critical to maintaining tiny round holed groups.

I have not yet tried jumping bullets but know it works as one of my shooting mates jumped his bullets by .009 season before last and shot very well. I don't know if the OAL thing is as important in that scenario but I am guessing it is.
 
Dean Breeden said:
SGJennings....
Please don't load 33.5 to 35 grains of N120 in that case I wouldn't want to be anywhere around if you that happens!:eek:
Click to expand...
I read and understood that the 33.5 to 35 was for H4198 in a 30BR.

The "relatively mild" load that I spoke of was 30.4 grains of N120 behind a 118 HillBilly with .001 neck tension just a skosh into the lands. It's a pussycat load and shot small holes.

I'm now evaluating a load starting with as much jam as will let me extract a loaded round and .003 tension. I'm starting low on the powder and coming up in .2 increments.

If nothing else, it provides mental distraction what with all the danged snow.
 
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my experience

SGJennings said:
I read and understood that the 33.5 to 35 was for H4198 in a 30BR.

The "relatively mild" load that I spoke of was 30.4 grains of N120 behind a 118 HillBilly with .001 neck tension just a skosh into the lands. It's a pussycat load and shot small holes.

I'm now evaluating a load starting with as much jam as will let me extract a loaded round and .003 tension. I'm starting low on the powder and coming up in .2 increments.

If nothing else, it provides mental distraction what with all the danged snow.
Click to expand...



with using fast powder in the 30 BR is they will go from shooting tinny holes to having brass flow back into the ejector pin hole in a very slight increase in powder when one is near the top of the spike. When one has to take their barrel off, if they can get it off, to open their bolt, one starts to think about consequences a bit more.

That old saw about if ya look out the winder and everyone is running down the street in the same direction it probably isn't a considence do have some meaning at times.
 
From an earlier post
I'm shooting a 30 Major which is a 6.5 Grendel necked up to 30. I've only tried N120.
Click to expand...

So, there is a whole slew of people running down the street to shoot something else in a 30 Major??? Feel free to convey your sage wisdom.
 
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GRENDEL case not BR

Pete Wass said:
with using fast powder in the 30 BR is they will go from shooting tinny holes to having brass flow back into the ejector pin hole in a very slight increase in powder when one is near the top of the spike. When one has to take their barrel off, if they can get it off, to open their bolt, one starts to think about consequences a bit more.

That old saw about if ya look out the winder and everyone is running down the street in the same direction it probably isn't a considence do have some meaning at times.
Click to expand...

Pete and others.
Mr Jennings is speaking of the GRENDEL case.
I shoot Tubal 2000 in mine. Nasty.....:D
 
Tubal 2000 is the other powder I considered to be "Tier 1". Alas, I couldn't find any when I was buying.

I have some Reloader 7, but *only* as a backup. Haven't even tried it.

Greg J.
 
6.5 Grendel necked up to a 30

Other powders for the RCH N120, 4227 both of these kill cases Tubal 2000 leaves a lot of unburned powder in the barrel. Ive used lots of this powder and won some matches with T-2000. H-4198 Can't get enough in the case and keep the bullet in the case no matter how much neck tension! Found N530 now we got something working.......... I can get as much powder as a 30BR holds even more if needed and still have room for a bullet. Shoots great and the barrel has no powder residue left behind.
 
isn't tubal and vectan some of the powders dynamit nobel no longer imports?
have you tried aa2230? it is a very versatile powder.
 
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