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Have any of you with ARs in 6mm Creed had issues with heavier bullets like the 108 eldm moving in the neck when they go into battery? Or under recoil? I loaded some test loads at Hornady's OAL 2.79 in Starline SRP 6mm brass It's raining so much I haven't gotten to shoot yet but I did some tests inserting a mag and sending a cartridge into battery. No powder or primer to start with. Just headspaced and sized to .002 neck tension. On extraction each cartridge had lengthened (projectile movement) by around .005.
So I did a slight taper crimp but still the bullet moved. So I decided to seat the bullet to where the top of the bullet was level with the bottom of the sized portion of the neck. Around 2.70 OAL. This helped but there is still slight movement. I had better results with Hornady 6.5 CM brass necked down to 6mm and seating the bullet to 2.70. Bullets did not slip there. But bullets slipped in the Hornady brass also when seated to 2.79. But only .0025 or so. I'm thinking I may need to go to a bushing die and .003 neck tension to avoid movement when seated longer. I'd rather do that than taper crimp.
Of note. Sierra 85 grain HPGK's do not slip at all and are a Royal Pain to pull the bullet using the inertia puller. But I would like to use a higher BC bullet with the longer ranges I deal with. I'll use up the 85s on shorter range meat does and hogs. I'm thinking the addition or subtraction in bullet weight provides more or less inertia when the cartridge slams home or even under recoil though recoil is slight in this caliber. Especially in a 10 plus pound all in AR. That's physics 101.
I've already ordered some 95 grain TMKs to try. If for nothing else than projectile ID because I have a ton of red tipped 6.5 bullets around. If the TMK shoots well, kills well, and doesn't move in the neck it is likely the bullet I will be using. It and the 85 HP use will also open up the prospect of using several of my medium burn rate powders also as I am well stocked in that department.
So I did a slight taper crimp but still the bullet moved. So I decided to seat the bullet to where the top of the bullet was level with the bottom of the sized portion of the neck. Around 2.70 OAL. This helped but there is still slight movement. I had better results with Hornady 6.5 CM brass necked down to 6mm and seating the bullet to 2.70. Bullets did not slip there. But bullets slipped in the Hornady brass also when seated to 2.79. But only .0025 or so. I'm thinking I may need to go to a bushing die and .003 neck tension to avoid movement when seated longer. I'd rather do that than taper crimp.
Of note. Sierra 85 grain HPGK's do not slip at all and are a Royal Pain to pull the bullet using the inertia puller. But I would like to use a higher BC bullet with the longer ranges I deal with. I'll use up the 85s on shorter range meat does and hogs. I'm thinking the addition or subtraction in bullet weight provides more or less inertia when the cartridge slams home or even under recoil though recoil is slight in this caliber. Especially in a 10 plus pound all in AR. That's physics 101.
I've already ordered some 95 grain TMKs to try. If for nothing else than projectile ID because I have a ton of red tipped 6.5 bullets around. If the TMK shoots well, kills well, and doesn't move in the neck it is likely the bullet I will be using. It and the 85 HP use will also open up the prospect of using several of my medium burn rate powders also as I am well stocked in that department.
