105 Amax load workup - Beginner needing advice.

[Rmitch223]

Let me start by saying I am completely new to reloading.
My step dad recently bought me a Hornady LocknLoad kit to start reloading. Ive reloaded with him only a few times and I plan to study and learn as much as I can before I get started. I'm building my bench now and getting everything lined out to get started.

I'm currently thinking a lot about my initial load work up.
I'm going to be shooting 105gr Amax bullets threw a Rem 700 SPS Varmint in .243.

A friend on mine loaded up the following load for me that shot 1/2" groups at 100yrds.

105gr amax
42.5gr of IMR 4350
Federal 210M primers
Seated at 2.800 COAL

The COAL is longer than all my reloading books state. Is this too long? Feeds well and shoots well I just want to be safe.

I'm curious since this load shot so well that I should just duplicate it. But reloading manuals I have looked at recently say that this is too high of a charge weight and its exceeded max pressure by 6000lbs. (66,000lbs)

Is this a safe load to start with?

Should I start at 38gr and work up to it in .5gr increments?

The fired brass show a slightly cratered primer where the firing pin hits it, but the edges of the primer are not flattened. I will add pics of the fired brass soon. Is this a sign or too much pressure or is it just because the Rem 700 firing pin hole is larger than the firing pin?

Any advice would be greatly appreciated.
Please advise if any information needed to answer my questions is not provided above.

Thanks,

Ryan

 

[Sully2]

Hodgdon's data shows with that same bullet...an OAL of 2.760"...with IMR 4350 a MAX of 40.2 grains at 2870 FPS..???

36.7 grains is their published min load...

You might go here....http://data.hodgdon.com/main_menu.asp....for some info especially min-max info.

 

[SBruce]

Could chronograph those loads you already have.

Velocity should be over 2950'/sec maybe even over 3000 if it's a warm or near max load IMO. Factory ammo with 100grn bullets is often advertised at around 2950 give or take a little. Usually based on 24" barrels, if your barrel is longer you should be a little faster and shorter should be a little slower.

Also, can you chamber empty recently fired cases without FL sizing and with minimal effort to close the bolt?? They should almost feel like the ones that haven't been fired yet.

IME, if you can neck size and rechamber without difficulty or an uncomfortable amount of force on the bolt handle twice (only need to FL size every 3rd firing) then it is not a max load. The need to FL size every other fireing is max or close to max, and needing to FL size every time to rechamber the brass is too much...............This can vary some with cartridge design and brass brand even brass lot, but if you have to FL size to close the bolt with anything more than minor resistance, it's probably right up there in the MAX load category if not over max.

Remingtons can often cause primer crater even with mild loads, primer flattening and especially shiny round or oval spots on the base of the case (indicating brass flow into the ejector hole) are better indicators of too much pressure.

Sticky bolt lift after fireing is definately a hot one and should be avoided at all cost IMO.

 

[Rmitch223]

The COAL has been something I haven't completely wrapped my head around yet. I understand that it can be unsafe to seat them to far away from the lands and too close as well. That's why I put so much thought into making sure I do it correctly. The loads I previously shot loaded at 2.800" functioned and shot extremely well, but I don't know if they are jamming into the lands or not. Another thing that kinda confuses me is that SAAMI spec for COAL is 2.710" and I'm shooting very accurately loaded at 2.800". I'm just concerned this is too long I guess. I will know when I get some dial calipers I suppose, I'm just confused about it right now and probably making it more difficult than it really is.

 

[backwoods83]

All rifles are different of course, but with a saami spec chamber in 243win, your max OAL should be about 2.885-2.905" before touching the lands, the amount of jump your using is what's keeping it safe, that's to high of a charge with that bullet jammed. I would not use that load in Lapua or Federal brass either due to less capacity. Full length size a case, polish the inside of the case neck, seat a bullet at 2.975", then use bolt force to chamber it, take that measurement and seat your amaxs .030" or .060" shorter, that'll give you about the best accuracy (normally) and start at 41grns, also I've found in most case H4350 works better in a 243 as does H4831sc.

 

[land308]

I use r&p brass. cci large rifle primers and 39 grains of imr4350. This shows very little pressure in my savage 12 fv and my velocity in 3023fps. once i hit the 3000 fps mark I saw no reason to go any hotter. I am on my 5th firing on the brass and primer pockets are still nice and tight. I dont like any cratering around the firing pin but i have seen rifles with larger firing pin holes that did leave craters easily. Get a chronograph or shoot it to distance and calculate the velocity based on the drop. Good luck

 

[Rmitch223]

Ive worked up from 37gn to 40gn and the rifle is shooting very accurately with 40gn. I'm not sure I will push it anymore. I may try 40.5 and 41gn in the future but right now I'm pretty happy. Shooting 1/2" groups at 100yrds now and 1" groups at 200yrds. I'm very curious as to what velocity I'm getting with this load. Gonna have to get a chronograph asap.

 

[midwesthunter]

When reloading you will get different pressures with different cases brands as they have a different capacity. I believe win brass has the highest capacity? I tend to like a compressed load myself. I haven't loaded any 105's recently as mine didn't like them but will see what I'm loading my 75 vmax's, I'm pretty sure its over max charge, but there is no pressure issues. With any reloading always work your way up, and back off if bolt gets sticky.