270 Win Load for Caribou

[Army SGM Retired]

ALL, I'm just starting with this rifle reloading and want to do it correct. Have loaded pistol cases a long time ago so but this is a first for the 270 Win. in a Browning A-Bolt. Let's get to the heart of this. When they say start at minimum powder grain and work up, what is the "work up ratio/scale"? By .5 or .2,.1..etc?? I loaded 17 rounds today in increments of .5 starting with H4831sc, 54.5 gr pushing 140 AccuBond in Winchester brass and WLR primer. I hope to shoot next week with my new chronoy and led sled. Am I on the correct track? The other concern is "To The Lands (TTL)" OAL, wow what a headache! Did all the checking for the measurment just to find out it won't fit in my magazine, darn!. It comes out to be .0525 off TTL. With That said should I worry about the OAL? I'm loaded at 3.3795 OAL not which is over the max length but well off TTL. Help in Alabama

 

[DrMike]

Welcome to the forum. It is good to have you on board. I certain you will discover some really quality people here, and undoubtedly you will be able to offer some insight at various times in days to come.

With the Browning A-Bolt, you almost always will be compelled to load to the magazine. In other words, you will have to load so that cartridge fits the magazine.

Minimum powder charge usually refers to the minimum listed in the recipe you opt to use. If the recipe you are using does not have a minimum powder charge, verify that it is from a reputable site, at least until you are comfortable discerning what appears legit and what does not. If you lift data from a reputable manufacturer of bullets and/or powder, you can almost always be certain that the data has been pressure tested and is safe at the charges listed. If it is just thrown out, it is only as valid as the person posting the data.

Assuming you obtained your data from either a published manual/guide, or from a reputable site, if no minimum is listed, drop back at least five percent. Some would suggest even dropping back ten percent, which is really not going to be much with the 270. For the 270, it is probably sufficient to work up a load in one grain increments until you reach maximum charge. For larger cases, 1.5% to 2% increments is not a bad way to work up toward maximum. If you are uncomfortable with that change, there is nothing wrong with working up in 0.5 grain increments. You will get the same results; it will take a little longer, but you are more likely to find a sweet spot.

Since you will not be able to play with seating depth very much, you will be forced to work with burn rates and charge to obtain the accuracy you want out of your rifle.

Check back on the forum from time-to-time as questions arise. There will always be someone willing to take the time to answer your questions. You should have a quality load shortly.

Consequently, when is your caribou hunt planned? Are you headed to Quebec or the NWT? Best of luck in that hunt. It can be a delightful time.

 

[SJB358]

Welcome to the site SGM! These guys on here are the best. So far, you look to be spot on with your load development. You are using one of the best powders for the 270 Win and the 140gr AccuBond is an excellent bullet. I usually load in 1 grain increments up to the max charge listed. Once I have found the powder charge that gives the best accuracy and the speed I am looking for, you can tune your length some to get your groups tighter. Since you have a chrony, you are in great shape, it will give you a good idea of how your rifle is reacting to each different charge.

I wouldn't worry about loading to the lands on your rifle. I usually start at max magazine box length and work back from them, 1/4 turn at a time on the seating stem. I wouldn't be surprised if you find what you are looking for at the factory COAL. Scotty

 

[hubcap]

SGM: Nosler recommends .050 to .100 off the lands with accubonds. For the best accuracy I ended up at .065 off the lands with 140 AccuBond. Your powder and component choices should get it done. :wink:

 

[Army SGM Retired]

Thanks for the info DrMike that was some good news. I'm using the Nozler #6 book for my loads. I just could not understand the difference on OAL of factory and my magazine limit OAL. As for the hunt I am heading off the northeast of Quebec first part of September so you can see I have a lot of shooting to do. This farming stuff I'm doing after 28 years of Army life takes up a lot of time. Ref my weapon, Browning A-Bolt, would I post a question ref the BOSS system that’s on it here at this "room" or under hunting?? Again thanks.

 

[Army SGM Retired]

Scotty and Hubcap (wow, what and name), thanks for the info. In my reading the TTL seating was the only way to get accuracy and I was worried that I’m so far off should I go to my back-up 7mm but you have settled me down some. I have to figure out this BOSS system, not sure if I should stay away from adjusting it and only use charge/seating or play with it all. I want to be able to make the long shot if called upon so that’s why I’m trying to get accuracy. Is there that much difference in primer/case use for speed/accuracy?? The book listed Remington but I’m using Winchester, hope that’s OK? Do you suggest loading all kinds of variations and take to the range or keep it simple?

 

[Scott Spencer]

SGM, welcome from fellow Alabamian!! I can't wait to hear your report on your trip and see photos! I've always wanted to go on a 'Bou hunt so maybe I can pick your brain when you get back!

Have fun on the range getting ready as well!! That .270 should be awesome with the 140 AB!!

 

[chet]

usually when I'm restriced by magazine length, and after I've established a good baseline for a max load, I'll start trying different primers.

 

[DrMike]

Any time you change a component (even brass), it is a good practise to drop back 5% and work up. Different cases have differing capacities and thickness which can give significant differences in pressure at maximum charge. Different primers burn with differing intensities. Generally, Remington primers are "cooler" than Winchester. It is more important to work up with whichever components (especially brass and primers) you have on hand than to precisely match what is written in a recipe.

I can't imagine that anyone will get too bent out of shape if you pose a question concerning your rifle here, but you may find more answers posting in the Rifle forum. There is almost certain to be someone who is familiar with the "BOSS" system. It has been over 15 years since I even handled one. We just never see them here. The system worked well, but it just never captured the imagination of the shooting public.

Hubcap, I have never read that particular information concerning the AccuBond. Could you provide me the reference for that? That approximates the recommendations regarding the E-Tip, however. With monolithic bullets, the longer jump to the lands is beneficial to accuracy, and necessary to control pressure.

Best of luck on your hunt, SGM. You are certainly under pressure to get your load development wrapped up and gain some confidence with your rifle.

 

[rick smith]

Work through the magazine and not be into the lands, two most important items. Rifles have more than one sweet spot when you are working with seating depth. Just finished a 338/350 Rem Mag using 180gr NBTs. I am about 0.150" from the lands. Shoots very well. The seating to the lands started with bench rest shooters, single shot rifles. There is no magic being at the lands, just a starting point for seating depth.
I have worked with the BOSS system a few times for friends. Best I recall we set the BOSS at a certain number, 3 ?, and shot the different loads. Picked the best load, then moved the BOSS in small increments and fired the best load at the different settings. The original paperwork with the rifle should have that info. If you don't have the paperwork check the Browning site. The BOSS system changes the barrel harmonics without altering your load. Basically the same thing we do when changing components/seating depth.
I use IMR-4831, all that was available in my area when I started loading. H-4831 will serve you well.Rick.

 

[SJB358]

SGM, I have a M70 338 Win Mag with the BOSS on it. It is one of my better shooting rifles. I think the BOSS is a great piece of gear, I actually think it is very easy to tune. I just work up my most accurate/full hunting speed load, at the factory setting, meaning, whatever weight bullet and caliber your manual calls for, and then tune the BOSS 1/10th of a turn at a time. I go slow, shooting 3 shots groups. You will either see your groups start to open or close. Once you get to the point of accuracy going the other direction, take it back to the last known good setting and you are done. I haven't had to shoot much more than 3 - 3 shot groups to get what I need. If you have any questions shoot them. The guys here are the best and won't bark at you for anything. They would have already done so with me if that was the case! Scotty

 

[Army SGM Retired]

Thanks DrMike, wow, one could send a lot of lead down rage just to try and find that one hole accuracy. I have only loaded Winchester brass but have Remington unfired also I will try next. So if the book states one case/primer pair I should drop the powder load by 5% of the base/start load? This could take a while but will do it correct the first time.

BREAK

Rick, Thanks for the info on the BOSS. I bought the gun second hand so I don’t have the book but will go to Browning for help. I loaded IMR 4831 loads today so I have two to try at the range.

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Thanks Chet, will try CCI next range day….

 

[Army SGM Retired]

Thanks Scotty for the info, should I unscrew the BOSS first to clean and start fresh or can you even take it off?? Not sure how that works. Know that there are numbers to keep track of the adjustment but will follow Ricks suggestions ref Browning website.

 

[SJB358]

SGM, for load development, I would stick with one case and one primer. More than likely you will get what you are after in regards to accuracy and speed. If you introduce another variable into the mix, it will just muddy the waters for you. Plus, once you have a set of new brass, you will likely have a set to develop loads for and then be able to load them practice and or hunting rounds, however it works out. Most fellers like use nearly new brass for hunting, just to keep Murphy at bay. Winchester brass is top notch in my book, so I think you will be in good shape. Looking forward to hearing and seeing your results. Scotty

 

[SJB358]

You can unscrew the BOSS and take it completely off the rifle and clean it. I have found this to be pretty easily done and doesn't require too much time. Mainly just carbon build up there anyhow.

I would take it off, clean it, then screw it all the way back on. Reset the numbers so it reads 0.0. That way you know where you are starting at. Then screw it up to the factory starting point and then begin your load work. Once you find the load that gives you the speed and good accuracy, then just turn the BOSS 1/10 of a turn at a time, while shooting 3 shot groups. You will get what you are looking for. The trick is to shoot slow and allow the barrel to cool plenty between groups.

I also included the sweet spot setting for you. Scotty

http://www.browning.com/customerservice ... asp?ID=109

 

[DrMike]

SGM,

You will note that Nosler usually lists three charges per powder for a given bullet weight. They also indicate which powder, under their test conditions, gave them the best standard deviation. That is usually a good powder to look at first. You will note that they generally list the three charges in two grain increments. The minimum charge is just that, a minimum. It is a good idea not to go below that charge, just as it is not a good idea to choose to begin at the maximum charge. Three sets of loads at two grain increments will give you a ton of data, and permit you to focus on a more narrow range for the second set of loads.

It is possible to get one hole groups, but sometimes the law of diminishing returns needs to be applied. I often remind people that super accuracy is one aspect for them to observe, but terminal performance of the bullet must also be factored in. Fortunately, with quality bullets such as those provided by Nosler and many other manufacturers, the bullets will do the job for which they were designed. However, we must keep in mind what the purpose of that bullet is and the performance parameters for efficient performance.

The chest on a deer is approximately eighteen inches deep; the chest on a caribou somewhat deeper. A one inch group--even a two inch group--will shoot accurately enough to kill deer-size game to well over 400 yards. We all want the confidence that comes from a load that gives us one-hole groups. However, sometimes we just run out of time and have to trust the one-inch load to do what must be done. If you lack confidence with your load, you may need to hunt and get closer.

 

[Army SGM Retired]

Thanks Scotty, it’s on my to do list tomorrow. Will clean and set to 3 and go from there. If you are ever passing through North Alabama or visiting our Marine Training Detachment at Redstone Arsenal drop me a line. The schools is heading toward you neck of the woods next year, Ft Eustis. Thanks.

 

[Army SGM Retired]

DrMike, Once again you are on target with information that keeps me going. The sub-inch groups are good to talk while on the bench but not to realistic off hand but got to practice. The next order of events after grouping is zero at 100 yards for impact out to XXX yards. I hope to use the Nosler Book and charts in back using velocity for the correct impact. I hope you can give me some words of wisdom ref all those numbers and how close they track with real yardage factoring wind/weather.

 

[DrMike]

For whatever it is worth, in preparation for the hunt I shoot from various field positions. If I can put nine out of ten into a paper plate from field position, I'm squared away for that distance. When I can no longer put them in off hand, or from rice paddy squat, or kneeling or sitting, then I bring the plate back until I can hit it consistently. That is my limit. As I age, and as upper body strength diminishes, the distances to target grow shorter, and I am forced to hunt.

The ballistics are fairly accurate as the calculations are simply an application of mathematics. You will need to dope the wind when you are shooting in the north, but MPBR is an application of ballistic principles to the projectile you have launched at ranges under 450 yards. If you launch your bullet at 2950 fps, you will have a zero range of 250 yards and a maximum point blank range of ~294 yards (the bullet neither rising nor dropping more than 3 inches from line of sight).

 

[Army SGM Retired]

DrMike, I still have the shooting skills from the over 28 years of Army and coupled with only 53 years young I hope to hold on target. Having never seen a Caribou I’m trying to figure the zero distance for that long shot without holding 2 feet over back of which I will not do. I just want the capability if it’s the last day and my tag is empty. I have had tag soup Elk hunting and it does not taste good at all. This hunt to Labrador is a once in a lifetime with my son and I so it sure would be nice to bring some good meat back instead of paper.