105 Amax load workup - Beginner needing advice.

[Ryan M.]

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.
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.


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

 

[Kingfisher]

In the interest of safety, yes, I'd back it down to around 38. As soon as I read the charge weight I was thinking "That's way over...". A look at Hodgdon's website shows that you're over their recommended max by almost 2.5 grs. For me anyway, that’s pretty significant. In my experience primers can be pretty subjective. Still though, they’re an indicator. I would definitely back it down.

 

[eric32]

Also try IMR4831 or H4831sc, they work a bit better with the 107/105gr rounds.

 

[normmatzen]

On the other hand, you may have an accurate load due to the high velocity. I would guess the barrel has a spin rate of 1 in 10 or so? Do you know? Usually, for 243 WIN loads with 105gr bullets, the MV will be around 3000 fps and not fast enough to stabilize that bullet. Usually, heavy bullets need 1 in 8 barrel to stabilize.
I shot a 243 for a couple years in Long Range BR and used H1000 powder as it supposedly is easy on the barrel. I used 46 gr which was nearly a compressed load and gave me ~3000 fps.

 

[groundhogbuster]

I have been working with the same gun with the 1/9.125 twist. I went the OCW route and found H1000 (45.9g) under the 105 a max shoots sub 1/2" groups very consistently. I worked from 48g in .3g increments, and my first group @ 100 was a .221". This is the best powder by far to push these 105's out of these guns. I worked with 4350, 4831, Retumbo, and H1000, and it was a bit better than Retumbo (.674") I shot my best group last weekend at 600, 3 shots was 2.6". Very good load, but be sure to use Magnum primers. Good luck

The gun in a BC stock, skim bedded and a homemade paint scheme to help blend. BTW I was getting 2960-2975fps out of this load with Win brass, Win Mag primer, will be shooting the fireformed this weekend

 

[Ryan M.]

I'm curious as to why you recommend magnum primers?

I have found that 40gn of IMR-4350 will shot 1/2" or better at 100yrds and this last weekend I shot a 1" group at 200yrds. I worked up to 40gn from 37gn in .5 gn increments.

I'm using Federal 210M Primers and Lapua brass.

 

[drumcorpschamp]

If you don't already have them, get the books ABC's of Reloading and Handloader's Digest. Tons of info for you to absorb. These books give a novice handloader a very good grounding in the activity.

Jerry

 

[Scott Harris]

Ryan,

Which reloading books are you using? if the answer is "none," that is the first thing you need to fix. Do not rely on your friend's advice: get a manual. Many people load over the maximum recommended load: don't trust your safety to the advice of friends. As mentioned, 42.5 gr IMR 4350 is more than 2 grains over the max recommended load published by Hodgdon. This may or may not be ok....probably not. If you are just starting, you should get several reloading manuals: Sierra, Hornady, Berger, etc. Read all the instructional sections: each will provide something new. Then look at the max published loads for each manual. There will be some variation among the manuals, but you will see clusters of charge recommendations. Then when your friend recommends a charge weight several grains above any of the manuals...you will know that recommendation is probably not safe.

Here is the best way I know of to determine how hot your load really is: repeatedly shoot the same piece of brass with the charge weight in question until your primer pockets noticeably loosen: i.e. you can seat a new primer with little to no force. When this happens after:
1. 1-5 firings: you have a very hot load that may not be safe.
2. 6-10 firings: you have a hot load, but safe
3. 10-20 firings: you have a safe load and know how to maximize your brass life.

 

[normmatzen]

I built a 243 WIN LR Bench rest gun a few years ago and used 105 AMAX for a while. My barrel was 1 in 8 so stability was not a problem.
I switched early on to H1000 as the word was it is easy on barrels. I believe it now as I used 46dr H1000 in a 28" barrel and coated barrel and bullets with hBN for a MV about 2900fps. The barrel was removed at 2500 rounds. It still shot well, but I went the 6BRX route and haven't looked back! Incidentally, the 46gr was determined by ladder tests and success at 600yd and 1000 yd.

 

[Clancy]

I really like alliant powders. It seems that appropriate charges of the most suitable fill cases nicely. I like RL19 with that 105 amax. Shoots groups under .2" from a 22" LV Krieger. The barrel is my old race gun I cut back and had rechambered. In MY RIFLE, hornady suggested loads shoot extremely well.

 

[CPorter]

42.5 grains is over max in the reloading manuals but that is also for a COAL of 2.71". According to quickload moving the bullet out to 2.8" reduces the pressure, assuming it isn't in the lands, by 3000 psi and right at the limit. Velocity through a 26" is calculated at 3004 psi.

In my testing on my Rem 700 VLS I found the magnum primers, Fed 215 in my case, reduce extreme velocity spread and standard deviation in extruded, stick, powders.

Take a case and saw down the middle of the neck and then clean up the cut with a jewelers file. Take a magic marker to the base of a bullet up to the point you usually seat it. Insert in the case you modified so it just stays in. Chamber it and then carefully remove it. You may need to use a cleaning rod to gently tap it loose. Where it was forced into the bullet should have lost the magic marker. If it moved getting it out the chamber hopefully the magic marker scrapes will show you. Anyway measure the cartridge as it came out and that should tell the COAL to touch the rifling.

Like the others have mentioned, please get yourself some reloading manuals.

 

[savagedasher]

According to Quickload your load has 60298 psi the case has max pressure 60191 psi If you were seating at 2.710 length your pressure would be 62957 psi. By seating the bullet that long you increased the usable case capacity 1.6 gr. My self I would load it down .02 .04 .06 of grain. When you get vertical you have went to far. At 2.710 your a full grain over max Good Shooting Larry

Happy New Years

 

[archerross]

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.
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.


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

In my experience primers can be pretty subjective.

IMHO, you have answered your own question. You've already shot these loads; they are accurate; they feed/cycle properly; and as Kingfisher said, primers can be subjective. Perhaps try a different regular primer (ex. CCI BR2) and you may not see cratering. I say load and shoot. I'm currently working up a load with the 105 A-max, H4350, and Fed210 primers for a Rem 700 243 I just had trued and rebarreled. I always want to know the limits of my cartridges, so I start low and work up until I see pressure signs. I'm currently +2.5 gr over book max and zero pressure signs. Every gun is different. All of these fellows have offered good advice. Get a couple loading books and do what you feel is right.

Happy shooting!!

 

[Clancy]

With respect I disagree. A softer primer may rupture correct?

 

[archerross]

Yes, a softer primer may rupture. After a quick scan of the www, generally Federal primers are considered softer than CCI. This is consistent with my experience, where Fed 210M primers cratered whereas the BR2 did not, when fired using the same powder charge.

 

[CPorter]

If you are shooting these in cold or cool weather be advised that the pressure will go up as the weather warms up.

 

[Clancy]

In my opinion, there are only 2 primers.... 250s and 450s lol.
I'm not really what you would call open minded.

 

[Ryan M.]

Ive been shooting the 105gn Amax fairly accurately with IMR-4350 at 40gn.
but, I'm wanting to get away from the 4350 because of temperature sensitivity.

Ive been suggested to try Retumbo or H1000. I'm leaning more towards H-1000 now because from what I hear the Retumbo is more likely to be a compressed load at the 48.1 grains Ive been suggested to use.

 

[Raythemanroe]

Whats your Velocity at that charge? anybody?

 

[Ryan M.]

I do not have a chrono right now so I'm not sure.