75 gr BT A-Max #22792 loads and seating

Hi All
I’m reloading for a.223 Tikka T3 Varmint Stainless 1-8 twist and trying the 75 gr BT A-Max #22792 bullets with 23 and 24 grains of Varget. I find if I seat the bullet to the correct overall length of 2.260” the bullet looks like it has been pushed in to far as there is a grove around the neck and bullet, when shooting the accuracy is nothing special at all. What overall lengths is anyone else using with this bullet and does any one have some ideal loads to recommend with this bullet?
Thanks Mark

Well, you're loading for a bolt action, and the listed .223 OAL's are short to assure functioning in semiauto actions, so you have some room to play with. There are two things you have to think about: How long can you make it so that it will still chamber?, and, How long can you make it so that it will still feed from the magazine? Odds are the second number is the shorter length, but it should still be longer than the listed OAL. The greater length means your bullet has a shorter jump to the rifling and should give you noticably better accuracy.

I would do it using a dummy cartridge. Use an unprimed case and start very long, try to chamber it by hand, and then decrease its length a little at a time until the bolt closes properly. That gives you your first number: maximum length for your chamber/throat. Then, see if it will feed through the rifle's magazine, and it probably will not, but you never know until you try. Most likely you will have to decrease its length (again in small increments) until it will feed smoothly, and this will give you your second number: maximum functional length for your rifle. If you shoot different boolets in this rifle, or if you are continuing to try others to find what the rifle prefers, crimp the bullet in place and label the case with a marker so you can use it to set your seating die whenever you want to load this bullet in the future.

Every rifle has different preferences as to powder and charge weight, and one guy's pet load may (and often does) pattern like a shotgun in someone else's. Take the most accurate charge that you have found for that powder/bullet combination, then experiment with longer OAL's until your rifle shows you. If you are still not getting the accuracy you were looking for, try another powder or bullet.

Mark-
I was going to answer this one, but versifier beat me to it, and did a much better job at the word-smithing than I would have. I would only add this: As a general rule, I start a few thousandths off the rifling, (provided it will work through the magazine) for my OAL. I will generally experiment with several different powders and charge weights; I will do a LOT of experimentation with those before I start messing around with seating depth and finally cutting my losses and giving up on a particular bullet. YMMV, but in my experience I generally get the best accuracy from the longest OAL I can get away with. Hope this helps.

-Klaus

Many thanks for the quick replies, looking at the rifle magazine which is made of plastic it has a large solid block to the rear which I might be able to machine to cater for the longer OAL cartridges.
Cheers Mark

You may have enough room as is to improve your accuracy quite a bit without needing to resort to magazine modifications. (I'd also see what it will do with some Sierra 65grGK and/or 69grMK's, too.:-D )

My fav trick to find how long the throut is on a rifle is to get a unprimed case & cut down from the neck to the shoulder with a hack saw there by splitting the neck .I then push a projectile into the breech & gentely tip the rilfe muzzel down wards & let the projectile silp down until it conects with the rifleing (remember I said gently ) I then take the case & gently chamber it (the splits alow the case to open around the projectile ) Then remove the case very gentily ! Set your seating die to the top of the seated projectile & then remove the dummy case & turn the seating punch down about a 1/3 to 1/2 a turn this seats the projectile just off the lands ! (& hopefully it's short enough to feed through you magizine.


Dave

Quote:

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Originally Posted by d-o-k

My fav trick to find how long the throut is on a rifle is to get a unprimed case & cut down from the neck to the shoulder with a hack saw there by splitting the neck .I then push a projectile into the breech & gentely tip the rilfe muzzel down wards & let the projectile silp down until it conects with the rifleing (remember I said gently ) I then take the case & gently chamber it (the splits alow the case to open around the projectile ) Then remove the case very gentily ! Set your seating die to the top of the seated projectile & then remove the dummy case & turn the seating punch down about a 1/3 to 1/2 a turn this seats the projectile just off the lands ! (& hopefully it's short enough to feed through you magizine.


Dave

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I do something much the same way. I use a case fired with a light load, and the desired bullet fits snug in the case, and then drop the bullet gently into the chamber, chamber the case behind it, pull out dummy, then use the seating die to push the bullet in the case 1/2 a turn on the stem, and then crimp the bullet into the case. I then write which bullet that I used on the case with a sharpie, and then keep the dummy in the die box, and keep it in my "rats nest". The thing with my gun is that I can drop a 60 gn bullet in the chamber, and close a sized case with no resistance behind it, and pull out the case with out the bullet. And the 788 magazine was kind of short to start with... for me.
DANIEL/BS JR.

On reflection of this question . I wonder sometimes if the 75gn is'nt a little heavy for the .223 ? I think really the 60gn is the heaviest I'd like to load . I've always considered the 75gn weight to be better suited to the 6mms? But that's just my opinion .

dave

As long as you've got the right twist (1 in 7 or 8"), they're are no problem. Lots of AR variants have the proper barrels and they are great long distance target bullets. My .22-250 won't really stabilize anything heavier than 55gr, or I would maybe have jumped on the heavier bandwagon. We can't use smallbore for deer hunting here, so I have is no practical need for them, but they are very popular in areas where it's allowed.

Well the best results so far is with the Sierra 69g #1380 Match King and not with the 75 gr A-Max Hornady
24g Varget 75g A-Max OAL 2.36
25g Varget 69g Sierra OAL 2.28
The 2.28 OAL will still feed ok in the 6 shot magazine but measuring the OAL it can go to 2.37, I might try some Sierras at this length but they are difficult to single feed with the magazine design as found with the 75g A-Max.