300 H&H Accubond issues

[Pole Pole]

Factory Accubond 180 grain are very accurate in my H&H but I cannot come close to duplicating this accuracy in reloads. I am using 63 grains of IMR 4350 seating at factor COL of 3.6”. The factory primer and powder is unknown to me. I do note that the factory bullets are crimped while the bullets furnished for reloading do not have a crimping grove. The Nosler rep said the crimp was to meet manufacturing requirements and one is not needed. Any help on this issued would be appreciated. Also, as a side note I can get 7-8 reloads from the nosler brass but only one after firing factory interbonds before the cases separate. Thanks, jp

 

[Rick HOlbert]

Sir, I'd try some IMR-4831 if you have any. I get outstanding accuracy with that powder. And no, you don't need to crimp with this cartridge. Let me know if that works for you.

 

[wswolf]

63 grains of IMR4350 is two grains less than the maximum load in the Nosler Manual. You might try increasing the powder charge slightly. Modern powders tend to burn more consistently at 60,000 to 65,000 psi. I have produced very accurate loads in my 300 H&H with several bullets and powders including H4350, H4831sc, Reloaders 23 & 26, N560 and Hunter. Best accuracy was usually around 2850 fps. Hunter seemed most accurate at about 2750 and Reloder 26 was best at about 2950,

If you have a gauging tool, RCBS Casemaster or equivalent, check for bullet runout of your loaded cartridges. Runout greater than .005" can cause erratic groups. if you do not have a gauge roll a loaded cartridge on a mirror or other flat surface. If you can see the bullet tip wobble the runout is too great.

Sometimes the neck expanding stem in the sizing die can pull the neck out of alignment causing the bullet to be seated crookedly. Using a gauging tool check the neck runout after sizing without the expander and again after sizing with the expander. If the expander is causing runout try sizing with the expander backed out of the die by a turn or so or size cases without the expander and then expand necks by pushing the sixed cases up over the expander. One of these methods should result in straighter case necks.

Another possibility is that the stem on your bullet seating die is not a good fit for the bullet and pushing it in slightly crooked.

By "interbonds" I assume you are referring to Hornady ammunition. If the reloaded cases are separating at the base you might try partial resizing so the case shoulders are not pushed back. If the separations occur at the front of the case try annealing before resizing.

A case gauging tool can reveal problems you never knew you had.

Hope this helps.

 

[gillettehunter]

H1000 is an excellent powder to use in the .300 WM. Likely work as well in the H and H too. Although not required crimping sometimes improves accuracy. Wouldn’t hurt to try that.
Bruce

 

[fourfive8]

"Also, as a side note I can get 7-8 reloads from the nosler brass but only one after firing factory interbonds before the cases separate. Thanks, jp"

Think there might be a clue?^^
There is something way wrong but not enough info to even make a guess. Other than.... one firing before head separation indicates a huge headspace problem.

 

[PHOENIX PHIL]

Factory Accubond 180 grain are very accurate in my H&H but I cannot come close to duplicating this accuracy in reloads. I am using 63 grains of IMR 4350 seating at factor COL of 3.6”. The factory primer and powder is unknown to me. I do note that the factory bullets are crimped while the bullets furnished for reloading do not have a crimping grove. The Nosler rep said the crimp was to meet manufacturing requirements and one is not needed. Any help on this issued would be appreciated. Also, as a side note I can get 7-8 reloads from the nosler brass but only one after firing factory interbonds before the cases separate. Thanks, jp

A couple of suggestions:

1) Pull a bullet from factory load and weigh the charge.

2) Chronograph the factory loads.

This information will give you an idea of the powder burn rate that is in the factory loads and help may point you to a powder to use.

 

[gbflyer]

The factory Nosler 180gr Accubond loads are extremely anemic across a chrono. I get 2800-2820 out of them at sea level in a 26” barrel.

 

[TucsonFX4]

Lots of potential variables, to include how you settled on your current reload recipe. I like to start with velocity ladders to find nodes, then shot the nodes that stand out for groups, then pick the standout groups and mess with jump (measuring ogive, not COL). You might just need to change up a variable or two to get better results. I like IMR4350, H1000 also, but that’s for 300winmag.

 

[Pole Pole]

I settled on 63 grains of IMR 4350 because that is all I have and it shoots the Sierra 180 gr GK @ 1- 1 1/4” with 74 year old eyes. I tried from 62 to 65 gr. Without improvement in accuracy. Since I have not had issues with the Nosler brass I, maybe incorrectly, assumed that headspace was not the problem. Also, after firing the factory Hornady round it seems stretched. Maybe I got an one off bad batch but I am the fourth box with same results. Currently not set up to do runout. I’m headed to Alaska in May to hunt Arctic grizzly which are 350-400 pounds with shots to 200 yards. Any thought on using the 180grain GameKings assuming an old fashioned broadside shot. Thanks all, great information.

 

[TucsonFX4]

My comments are less about the brass’s reaction/sizing to your rifles chamber, and more about how big of a jump the bullet has from the loaded brass to the barrel’s rifling. Hornady makes some nice instruments to measure that and then you can determine that measurement for your specific rifle.

Regarding the GameKings for grizzly, you’ll get no shortage of bullet opinions here. I’ll share mine…I would want a tougher bullet for that hunt. I’ve seen that bullet work marvelously on a cow elk, but I still would rather use a tougher bullet for elk. My opinion is that bullet is best suited to deer and below. I believe grizzly would easily justify T/TSX, A Frames, Accubonds, and many more premium bullets, with an emphasis on mono metal or bonded to maximize penetration.

 

[Pole Pole]

I’m shooting a M70 made in 1957 which has a long throat therefore I’m limited by the length of the magazine. So 3.6” case length is about maximum. For now it seems the accubond is my best bet since I have a good supply and they are accurate. Other than the factory accubonds Hornady just released the new CX mono bullets. Has anyone tried these? Is griz getting tougher or are hunters wanting bullets to reach vitals from any angle? Hehehe. Just staring the pot. Thanks

 

[sestoppelman]

Factory Accubond 180 grain are very accurate in my H&H but I cannot come close to duplicating this accuracy in reloads. I am using 63 grains of IMR 4350 seating at factor COL of 3.6”. The factory primer and powder is unknown to me. I do note that the factory bullets are crimped while the bullets furnished for reloading do not have a crimping grove. The Nosler rep said the crimp was to meet manufacturing requirements and one is not needed. Any help on this issued would be appreciated. Also, as a side note I can get 7-8 reloads from the nosler brass but only one after firing factory interbonds before the cases separate. Thanks, jp

If you are getting 7-8 reloads with one brass, then HS isnt likely an issue here, but rather your specific load.
As suggested you need to try other powders or bullets. Have had great results with Reloder 22 but good luck finding any these days. Your rifle might not like 4350.

 

[gbflyer]

I have had bad experience with Hornady 300 H&H brass. I ream a stub gauge for every barrel I chamber so I can better setup my dies. As we all know, every shouldered cartridge built on a belted case headspaces on the shoulder after the first firing. The Hornady brass I had is .035 short from shoulder datum to case head. Nosler which I believe is Norma, Norma, and new old stock Winchester all are within a few .001’s. I got 2 firings from the Hornady, then the case heads begin to separate. I can only surmise that the initial stretch is too much. I get multiple firings from everything else.

Another place belted mags run into issues, in my experience, is with the do-all go-gauge. Mine is extremely generous. I’ve started setting them up with brass instead.

 

[Desperatezulu]

I agree wholeheartedly with Gbflyer on Hornady cases in the H&H. I'd love to say they are junk but alas SA manufacturer PMP also makes cases for the 300H&H and they steal Hornady's prize in the true junk status.

My own experience is that Hornady cases not only don't give great accuracy in my gun, for reasons I have never been able to fully pin down, but are also susceptible to case head separation. Gbflyer's explanation could well be on the money. I'm only keeping the Hornady's in case I one day cannot get better cases in this cal.

Norma are far superior in accuracy and longevity in my 300 H&H.

Factory Accubond 180 grain are very accurate in my H&H but I cannot come close to duplicating this accuracy in reloads. I am using 63 grains of IMR 4350 seating at factor COL of 3.6”. The factory primer and powder is unknown to me.

Running this load through GRT, recognizing that many critical parameters are unmeasured and therefore the default values, suggests a muzzle velocity right on 2800f/s for a 24" barrel. GRT suggests that your nearest accuracy/resonance node would be at 62.2gr @ an MV of 2775f/s.
At this velocity, you may as well run the 200gr AB's.

As others have said, there are many more optimal powders for this combo - of course a moot point of you only have IMR4350 to work with. My preference is RL-26.

So basically the advice seems to be use better cases (Norma) and a more suitable powder, assuming you can get your hands on both. Otherwise find more of that factory ammo that seems to work so well!

 

[Fabnosh]

I'd just follow the normal procedure for working up a load. You could probably benefit from chrono'ing the factory load to give you some idea of the speed you should be looking for (as I'm guessing the factory stuff is on a harmonic node or there about's) and then find a powder that gives enough scope for increase and decrease in 0.5 grn increments for a few grains. Then when the group closes up try 0.2 either side.

FN

 

[Pole Pole]

The Imr 4350 shoots the Sierra 180 gr gamekings well with 63 grains so not thinking it is the powder. It is unfortunate that the GKs will not kill a interior grizzly bear. I was in a Cabelas yesterday and found they had maybe 8 boxes of Nosler 180 grain Accubond @ $85.

 

[450 Dakota]

If you have access to a chronograph I would chronograph the factory loads. Don’t put any faith in what the box says the velocity is. Next, I would measure to the ogive of the factory loads that shoot good. Then I would load some with bullets seated to the same ogive length as the factory. I would shoot those and work my load to match the factory velocity.