30 cal 200 nosler accubonds
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Hired Gun
Well-Known Member
I seat at 3.7" and get consistant sub 1/2" moa at .375" from the lands. I am getting great results with IMR-7828. I use 85.5 grain with a CCI-250 primer in the 300Wby.
Jtomlinson
Well-Known Member
I am going through exactly the same process at present but in a .300 Win Mag sendero SFII.
I am still using H1000 as stocks of Retumbo in the U.K have run out for present.
To date I have had no luck with loads seated to regular factory lengths so on my next batch I intend to move the bullet (200 grain Accubond) to .010" back from the lands and work backwards in .005" increments from there until acceptable accuracy is attained.
Rounds seated at .125" back showed no inclination whatsoever to group save in the case of one factory load, this being the GECO 180 soft point, a run of the mill bullet, not bonded or anything special, but nevertheless one which puts 3 shots well inside 5/8" at 100 yards.
Had this been a high BC bullet I would be tempted to stick with it for all hunting, hence my desire to obtain good accuracy with the Accubonds. I know they are a good accurate bullet so I just need some spare time to try out different load configurations.
You should be able to obtain good accuracy with the load set up you have there, again sounds like you have not yet found the ideal seating depth.
Have you carried out any mods to the Sendero such as lighten trigger pull or skim bedding?
I am still using H1000 as stocks of Retumbo in the U.K have run out for present.
To date I have had no luck with loads seated to regular factory lengths so on my next batch I intend to move the bullet (200 grain Accubond) to .010" back from the lands and work backwards in .005" increments from there until acceptable accuracy is attained.
Rounds seated at .125" back showed no inclination whatsoever to group save in the case of one factory load, this being the GECO 180 soft point, a run of the mill bullet, not bonded or anything special, but nevertheless one which puts 3 shots well inside 5/8" at 100 yards.
Had this been a high BC bullet I would be tempted to stick with it for all hunting, hence my desire to obtain good accuracy with the Accubonds. I know they are a good accurate bullet so I just need some spare time to try out different load configurations.
You should be able to obtain good accuracy with the load set up you have there, again sounds like you have not yet found the ideal seating depth.
Have you carried out any mods to the Sendero such as lighten trigger pull or skim bedding?
600Nitro,
Have you tried any faster burning powders in your 300 Win Mag and 200 gr Accubond? I am doing some load testing with a couple of 300 win mags with this bullet. I am finding that I can get just as high of velocity with burning rates like IMR 7828 and RL22 but with 6 or 7 grains less powder than H1000 and minimal load compression at magazine length. I would think that you would have to cram a lot of Retumbo in the case to get max velocity.
Just some food for thought.
Have you tried any faster burning powders in your 300 Win Mag and 200 gr Accubond? I am doing some load testing with a couple of 300 win mags with this bullet. I am finding that I can get just as high of velocity with burning rates like IMR 7828 and RL22 but with 6 or 7 grains less powder than H1000 and minimal load compression at magazine length. I would think that you would have to cram a lot of Retumbo in the case to get max velocity.
Just some food for thought.
lerch
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The accubond is a fairly thick jacketed bullet so it may like a little bit of a jump to the lands, something you might wanna try. In the opposite direction you might just touch the bullet to the lands or even in .005 in the lands. If you do this back off your load a little bit and work back into it, gotta watch those pressures.
good luck
steve
good luck
steve
G
Guest
Guest
[ QUOTE ]
In the opposite direction you might just touch the bullet to the lands or even in .005 in the lands. If you do this back off your load a little bit and work back into it, gotta watch those pressures.
[/ QUOTE ]
IMAO - great for ivory tower BR loads, bad for hunting. Anything tighter than .030 off the lands with custom a chamber and you'll have some cartridges jam into the lands and stay there. Eject the cartridge and powder pollutes the magazine. Now try to chamber another round and a few loose grains you missed while field cleaning the dumped powder prevents bolt closure. I did this with two of my custom guns (which are 20 times harder to find the lands than a sloppy factory chamber). Luckily I was only varmint hunting in the first case and deer hunting with a backup in the second case. Note I had tested (chambered/ejected) each round before the hunt. I suppose with run-out changing, temp changes, one managed to jam. (I was .010 off the lands).
When I read folks talking .015 or tighter off the lands, I suspect they don't have reliable loads OR are not really that tight OR have a sloppy factory chamber OR they are real good and know their stuff. I know some guys have the skills to measure this tight and produce robust loads, but after a year of trying I gave up. Lucky for me my Kirby built guns seem to shoot great even backed .050 off the lands.
In the opposite direction you might just touch the bullet to the lands or even in .005 in the lands. If you do this back off your load a little bit and work back into it, gotta watch those pressures.
[/ QUOTE ]
IMAO - great for ivory tower BR loads, bad for hunting. Anything tighter than .030 off the lands with custom a chamber and you'll have some cartridges jam into the lands and stay there. Eject the cartridge and powder pollutes the magazine. Now try to chamber another round and a few loose grains you missed while field cleaning the dumped powder prevents bolt closure. I did this with two of my custom guns (which are 20 times harder to find the lands than a sloppy factory chamber). Luckily I was only varmint hunting in the first case and deer hunting with a backup in the second case. Note I had tested (chambered/ejected) each round before the hunt. I suppose with run-out changing, temp changes, one managed to jam. (I was .010 off the lands).
When I read folks talking .015 or tighter off the lands, I suspect they don't have reliable loads OR are not really that tight OR have a sloppy factory chamber OR they are real good and know their stuff. I know some guys have the skills to measure this tight and produce robust loads, but after a year of trying I gave up. Lucky for me my Kirby built guns seem to shoot great even backed .050 off the lands.
Jtomlinson
Well-Known Member
[ QUOTE ]
600Nitro,
Have you tried any faster burning powders in your 300 Win Mag and 200 gr Accubond? I am doing some load testing with a couple of 300 win mags with this bullet. I am finding that I can get just as high of velocity with burning rates like IMR 7828 and RL22 but with 6 or 7 grains less powder than H1000 and minimal load compression at magazine length. I would think that you would have to cram a lot of Retumbo in the case to get max velocity.
Just some food for thought.
[/ QUOTE ]
As yet I have tried only H1000, my rifle is showing a real preference for bullets seated towards the lands, I would not attempt to try and hold at say .005" or less behind the lands as tolerances on differnet bullets, even from the same batch can cause variations sufficient to make this too indeterminate a method for me at least.
When seated to say .030" from the lands, the Accubond leaves sufficient space in my own cases so as not to have excess compression with 78 grains of H1000, yes there is mild compression, but nothing that troubles me. (As my rifle is in Win Mag it uses a shorter case than your own RUM so I have etra length capacity in my mag box than you will have for longer O.A.L rounds)
I agree that in an ideal world the rifle should shoot well with all factory ammo, no matter what the seating depth. At present however I am dealing with a factory spec rifle, with factory fitted barrel, as such this rifle will be intended (thorated) by the manufacturer to be able to accomodate, in safety, any of the commercially available factory ammo, which as far as I can see in .300 Win Mag ranges from 150 grains upto 220 grains.
Given the longish freebore, the use of a large number of these rounds will be a hit and miss affair as far as accuracy goes, you may hit lucky and find as least one, hopefully more, factory rounds that shoot well in accuracy terms. As an alternative to this is to do what most bench rest guys do and load to suit your exact rifle, in my case this has shown a preference to go close out to the lands. I would qualify this by saying I personally would not load to enter the lands, some do I know, but too many problems can arise this method, and for hunting IMHO it is best to avoid this if at all possible.
I personally see no problem in loading long, as long as common sense and care in load development is followed, after all you are fune tuning the ammo to your particulare rifle, much the same as race drivers fine tune the engine for their particular race car.
I have found, with load/pressure testing with Rel 22 that great variation can arise from cannister to canister for the same charge weight, no problem if you back off and re-test with each new batch of powder used, as probably you should do, and no problem if you are using low end loads, but if you are up to top book / pressure loads, a variance in burn rate can lead to pressure problems.
I have not tried it yet but beleive around 80 -82 grains of Retumbo will be required, as you say, this will certainly fill the case, to what level I cannot say, maybe with re-sized fired cases that load level will be no problem, others who have used Retumbo will know far better than I.
Maybe another way to go would be the use of H870, now discontinued I beleive but stocks of which seem still available or 869, however I have no experience with either of these, certainly being a spherical powder the lack of interstitional space in a charged case should permit maximum charges to be used.
I have both Rel 25 and IMR 7828 to try and will do so when time permits. Do you know if 7828 and 7828SC produce the same velocity for the same charge or is there a difference in burn rates, I am guessing the differnce relates solely to its ability to meter better much as with 4831SC
600Nitro,
Have you tried any faster burning powders in your 300 Win Mag and 200 gr Accubond? I am doing some load testing with a couple of 300 win mags with this bullet. I am finding that I can get just as high of velocity with burning rates like IMR 7828 and RL22 but with 6 or 7 grains less powder than H1000 and minimal load compression at magazine length. I would think that you would have to cram a lot of Retumbo in the case to get max velocity.
Just some food for thought.
[/ QUOTE ]
As yet I have tried only H1000, my rifle is showing a real preference for bullets seated towards the lands, I would not attempt to try and hold at say .005" or less behind the lands as tolerances on differnet bullets, even from the same batch can cause variations sufficient to make this too indeterminate a method for me at least.
When seated to say .030" from the lands, the Accubond leaves sufficient space in my own cases so as not to have excess compression with 78 grains of H1000, yes there is mild compression, but nothing that troubles me. (As my rifle is in Win Mag it uses a shorter case than your own RUM so I have etra length capacity in my mag box than you will have for longer O.A.L rounds)
I agree that in an ideal world the rifle should shoot well with all factory ammo, no matter what the seating depth. At present however I am dealing with a factory spec rifle, with factory fitted barrel, as such this rifle will be intended (thorated) by the manufacturer to be able to accomodate, in safety, any of the commercially available factory ammo, which as far as I can see in .300 Win Mag ranges from 150 grains upto 220 grains.
Given the longish freebore, the use of a large number of these rounds will be a hit and miss affair as far as accuracy goes, you may hit lucky and find as least one, hopefully more, factory rounds that shoot well in accuracy terms. As an alternative to this is to do what most bench rest guys do and load to suit your exact rifle, in my case this has shown a preference to go close out to the lands. I would qualify this by saying I personally would not load to enter the lands, some do I know, but too many problems can arise this method, and for hunting IMHO it is best to avoid this if at all possible.
I personally see no problem in loading long, as long as common sense and care in load development is followed, after all you are fune tuning the ammo to your particulare rifle, much the same as race drivers fine tune the engine for their particular race car.
I have found, with load/pressure testing with Rel 22 that great variation can arise from cannister to canister for the same charge weight, no problem if you back off and re-test with each new batch of powder used, as probably you should do, and no problem if you are using low end loads, but if you are up to top book / pressure loads, a variance in burn rate can lead to pressure problems.
I have not tried it yet but beleive around 80 -82 grains of Retumbo will be required, as you say, this will certainly fill the case, to what level I cannot say, maybe with re-sized fired cases that load level will be no problem, others who have used Retumbo will know far better than I.
Maybe another way to go would be the use of H870, now discontinued I beleive but stocks of which seem still available or 869, however I have no experience with either of these, certainly being a spherical powder the lack of interstitional space in a charged case should permit maximum charges to be used.
I have both Rel 25 and IMR 7828 to try and will do so when time permits. Do you know if 7828 and 7828SC produce the same velocity for the same charge or is there a difference in burn rates, I am guessing the differnce relates solely to its ability to meter better much as with 4831SC
